Several years ago, I came across this webpage on the internet. I don’t remember where, but I do know these are common mistakes many writers make. I hope you will find this advice as useful as I have.

For all intents and purposes, not for all intensive purposes

A dog eat dog world, not a doggy dog world

All in all, not All and all

Day and age, not day in age

Buck naked, not butt naked 

All for naught, not all for not

A whole different story, or another story, not a whole nother story

Ad nauseum, not At nauseum

Etcetera, not excetera

Safe deposit box, not safety deposit box

Supposedly, not supposably 

Undoubtedly or indubitably, not undoubtable

Regardless, not irregardless

Should have, not should of

Entitled not intitled or titled – one inherently deserving of special treatment.

Infamous – famous for a negative reason, for doing bad things. George Washington was famous. Bonnie and Clyde were infamous.

Insure – compensate for damages. Ensure – to make sure.

Affect versus Effect
Affect is a verb that means to have an influence on. Effect is a noun that refers to the influence. You would not use ‘affective’ to describe someone who gets things done. The word ‘affective’ is used to when describing moods, and especially when describing mood disorders. For example, ‘He has an affective disorder. We aren’t yet sure if it’s depression or anxiety.’ Also, for detective fiction, the phrase is ‘personal effects’ when referring to the property of an individual.

Poisonous versus Venomous
Poisonous refers to something that is toxic if you eat or drink it. Venomous describes something that is poisonous if it bites you. Snakes can be venomous; they cannot be poisonous.

Bemused – bewildered or confused, does not mean amused

Infer versus Imply. Infer is on the part of the listener. Imply is on the part of the speaker.

Between versus Among. Between deals with two people or things. Among deals with three or more people or things.

Lay versus Lie
A person does not lay down. A person may lay down a thing. You lay down your book. You lay down the law. Hens lay eggs. If you’re talking about a person lying down in the past tense, then the past tense is lay. If you’re talking about what you did last night, then you laid down. This is not to be confused with the past tense of the word ‘lie,’ when used to refer to a non-truth, in which case the past tense is ‘lied’ as in, ‘He told a lie. Therefore, he lied.’

Sit versus Set
If you’re talking about plunking your bottom in a chair, you want to use the word ‘sit.’ If you’re talking about placing an object, it’s ‘set.’

Principal versus Principle
The trick to keeping these two straight is to use ‘principal’ in reference to a person and ‘principle’ in reference to a standard, rule, or belief. Remember this: There’s a ‘pal’ in ‘principal,’ especially when the principal in question replaces detention with meditation.

Capitol versus Capital
Capitol refers to a building, specifically, the building where legislators meet. The term ‘Capitol Hill’ refers not to that Washington DC is the capital of our nation, but to the neighborhood that houses the building where Congress meets. Capital is pretty much every other use. It refers to the most important city or the governmental seat of a country, county, state, or other region. It refers to an upper-case letter. And it refers to investment funds.

Shone versus Shown
Shown is the past participle of the word ‘show,’ which is a verb meaning to ‘exhibit’ or ‘present.’ Shone is the past and past participle of the word ‘shine,’ which is a verb meaning ‘to emit light.’

Shone versus Shined
If ‘shone’ is the past tense of ‘shined,’ then why doesn’t anyone say ‘I had my shoes shone yesterday’? The answer is that in modern writing, it’s considered archaic (and therefore, wrong) to use the word ‘shone’ to refer to having shined anything so mundane as shoes, silverware, or windows. That said, it’s perfectly acceptable in modern writing to say that after you shined your shoes, your silverware, or your windows, they shone brightly.

Discreet versus Discrete
Discrete means individual, separate, or distinct. Discreet means careful, cautious, or evidencing good judgement. To remember the difference, think about one ‘e’ versus two. Use one ‘e’ to refer to something singular. Use an extra ‘e’ to show extra care.

Emigrate versus Immigrate
When you leave your country to permanently live in another, you emigrate. When you arrive in another country to live permanently, you immigrate.

Elicit versus Illicit
Elicit means to draw forth or to coax out. Illicit means improper. To remember which is which, think of the ‘e’ in ‘elicit’ as standing for the ‘e’ in ‘exit.’ If you think there’s something exciting about things that are illicit, consider that ‘illicit’ contains the root, ill.

Continuous versus Continual
Continuous refers to something that has no end, which is to say that if something continues ad infinitum, it is continuous. Continual refers to something that stops and starts. If you’re on a continuous search for connection, you might be lonely. If your search for connection is continual, then you might be a serial dater.

Further versus Farther
Farther refers to actual physical distance, a literal distance, as in ‘My car’s making a funny noise. How much farther is it to the service station?’ Further refers to a figurative distance, as in ‘How much further can this car go before I have to sell it for scrap metal?’

Bring versus Take
You bring things here. You take them there.

Home and Hone
Hone is always a verb. It means to sharpen or make more acute. For example, you can ‘hone’ a skill. Home is a noun also used sometimes as a verb to mean to move in toward a destination or target with accuracy. For example, you can ‘home in on that delicious smell and realize it’s freshly baked cookies.’  Although you might think that you can ‘hone in’ on a target, the proper word is ‘home.’ Remember if you need to add ‘in’ or ‘in on’ after the verb, you probably should be using ‘home.’ If not, then it’s ‘hone.’

Fleshing out versus Flushing out
If you’re talking about adding substance to something, like writing an article you’ve merely outlined, then it’s ‘fleshing out,’ as in adding flesh to bones. If you’re talking about finding something that’s not easily visible, then it’s ‘flushing out’ as in ‘flushing out the enemy.’

Viable versus Feasible
Viable and feasible are often, albeit incorrectly, used interchangeably. However, viable refers to whether something is capable of surviving. Feasible refers to whether an action is possible. Accordingly, a viable candidate must have a feasible plan.

Fewer versus Less
Fewer refers to items that you can actually count, like hours or dollars. Less refers to generalities, like time or money.

Perpetrate versus Perpetuate
To perpetrate something is to commit it. To perpetuate something is to continue it. If you perpetrate a crime, you perpetuate criminality in society.

Perquisite versus Prerequisite
Perquisite usually means an extra allowance or privilege. Prerequisite means something that’s required. To remember the difference, think of the film titled The Perks of Being a Wallflower. The ‘perks’ in the title are short for ‘perquisites.’

Pored versus Poured
When you’re talking about studying something intently, use ‘pored,’ as opposed to ‘poured.’ Pouring refers to what you do with a liquid. To help you remember, think of the pores of your skin. To see them, you must ‘pore’ over your face in the mirror.

Prescribe versus Proscribe
To prescribe something is to command or recommend it. While you can’t prescribe a person, you can proscribe a person or a thing. To proscribe someone or something is to outlaw him, her, or it.

Regretful versus Regrettable
Regretful means filled with regret. Regrettable means deplorable or unfortunate. Accordingly, one would be regretful over one’s regrettable actions.

Reluctant versus Reticent
These two words have to do with being less than willing to do something. However, reluctant describes unwillingness in general, whereas reticent is used only in reference to speaking. When one is reticent, it means he is reluctant to share his thoughts.

Sensual versus Sensuous
Both words refer to the senses. Sensuous refers to things that relate to the senses or even appeal to the senses. For example, a hand cream can be described as sensuous. Sensual also refers to things that appeal to the senses, but the connotation is erotic. For example, the way one applies their hand cream may be sensual. If you want to describe the lines of a painting, you might use the word ‘sensuous.’ To remember the difference, think of the word ‘sexual,’ which is more similar in spelling to ‘sensual’ than ‘sensuous.’

Appraise versus Apprise
To appraise is to assess the value of something. The word appraise is often used in connection with real estate sales. To apprise is to teach or inform. We at Reader’s Digest always seek to apprise you of what you want and need to know.

Assent versus Ascent
To assent is a verb that means to agree.
Ascent is a noun that refers to a climb, as in ‘the first ascent of Mt. Everest,’ or a liftoff, as in ‘the ascent of the balloon.’

Canvas versus Canvass
Canvas is a type of fabric that tends to be tough and strong.
Canvass is a verb that means to try to ascertain people’s opinions.

Illusion versus Allusion
An illusion is a misleading image or impression, such as an optical illusion. An allusion is a reference to something else, such as a literary allusion.

Defuse versus Diffuse
Defuse is a verb that means to render a bomb non-explosive (by removing the fuse, or otherwise). It can also refer to rendering a situation less dangerous. Diffuse is a verb that means to disperse over a wide area. Diffuse can also be used as an adjective that describes something that is not concentrated (in other words, something that might have been diffused). In the latter case, the word is pronounced with a soft s-sound, like the word ‘so,’ as opposed to a hard s-sound like the word ‘use’

Disassemble versus Dissemble
Disassemble is a verb that means to take something apart. Dissemble is a verb that means to lie.

Disburse versus Disperse
Both disburse and disperse are verbs that involve distributing things. But: disburse means to give or hand over money or funds. Disperse is a verb that means to scatter, and it has nothing to do with money or funds.

Disinterested versus Uninterested
Being disinterested doesn’t mean you’re not interested in something, but rather that you have no bias about it (as in, no personal stake). By contrast, being uninterested means you’re not interested or intrigued by something. If you think your spouse has lost interest, then you’re worried he or she is uninterested (not disinterested).

Eminent versus Imminent
Eminent describes something or someone prominent. Imminent describes something that is about to happen.

Emoticon versus Emoji
Both emoticons and emojis are graphical expressions used in electronic communication. An emoticon is a typographic display intended to suggest a facial expression. For example, the emoticon for a winky-face is a semi-colon followed by a right-parenthesis. An emoji is an actual visual image, and it need not be of a face. Rather, it can be virtually anything.

Remodeling versus Renovating versus Restoring
Remodeling and restoring are terms of art to architects and interior designers, and they mean different things: Remodeling means changing the structure of a space. For example, if you build a second floor on a ranch house, you are remodeling it. Renovating refers to significantly changing a space without changing its structure. For example, if you remove your bathroom fixtures and replace them with new ones, you are renovating the bathroom. If you start moving walls or adding new windows, then you’re remodeling. Restoring means returning a space to its original character or use. For example, removing vinyl siding and repainting the original wood siding of a house is a restoration project.

…versus Refurbishing versus Redecorating
The term refurbishing is a form of renovating. It refers to rebuilding or replenishing with new material. You can refurbish your wood floors as part of a renovation project. Redecorating means changing the character or scheme of a space’s decor. Redecorating is the least structural of all of the aforementioned ‘R’ terms. You can redecorate by bringing in a new sofa or hanging new posters on the wall. Remodeling, renovating, restoring, and refurbishing can involve redecorating.

Judicial versus Judicious
Judicial means ‘connected with a court of law.’ Judicious means ‘wise.’ Here’s a way to remember the difference: Not all judicial decisions are judicious.

Libel versus Slander
Both libel and slander are forms of defamation, which is the making of a statement about someone that is both false and derogatory. Slander is any oral publication of a defamatory statement. Libel is a written publication of a defamatory statement.

Alibi versus Excuse
As a noun, ‘alibi’ refers to proof you were elsewhere when something happened. When someone provides an alibi for you, they are offering that proof. As a noun, ‘excuse’ refers to any explanation of your behavior, it being understood that by offering an excuse, you are essentially admitting to the behavior.

Patent versus Copyright versus Trademark
Created something you think is awesome and you want to make sure you get the credit? If it’s an original invention of some kind, then you’ll want to get a patent. If it’s something you wrote that expresses an idea in a unique way, such as a work of fiction, you’ll want to think about registering the copyright. If it’s a slogan or logo that identifies a product, you’re talking about a trademark.

Your versus You’re
‘You’re’ is a contraction of two words: you and are. ‘Your’ is a possessive form of the pronoun, you. If something belongs to you, it is yours. If you write ‘you’re,’ then you should be able to substitute ‘you are’ in its place.

Their versus They’re
‘They’re’ is a contraction of two words: they and are. ‘Their’ is a possessive form of the pronoun, they. If they own it, it is theirs. If it belongs to them, it is also theirs. If you write ‘they’re,’ then you should be able to substitute ‘they are’ in its place.

They’re versus There
‘There’ refers to a place that is not here. If you are referring to a place that is not here, then that calls for the use of the word, ‘there.’ If you are using this word to refer to ‘they are’ or the possessive form of the pronoun ‘they,’ then you do not want to use this word.

It’s versus its
‘It’s’ is a contraction of two words: it and is. ‘Its’ is the possessive form of it. Here’s a rule you can use to remember the difference: Just because it’s possessive, doesn’t mean its spelling must include an apostrophe.

Nauseous versus Nauseated
Believe it or not, ‘nauseous’ actually doesn’t mean feeling sick to your stomach or afflicted by nausea—that’s nauseated. Technically speaking, every time you say ‘I’m nauseous,’ you’re saying that you cause or inflict nausea, as that’s the actual meaning of ‘nauseous.’ A way to use this word correctly would be, ‘I knew that the milk was rotten when I got a whiff of the nauseous smell coming from the carton.’ Smelling this nauseous rotten milk probably made you feel nauseated. ‘Nauseous’ has been used to mean ‘nauseated’ for so long, however, that many a dictionary editor has come to accept it as another meaning for the word.

Everyday versus Every Day
If you do something seven days a week, you do it every day. ‘Day’ is a noun, and ‘every’ is the adjective that modifies it—two different words. Meanwhile, everyday, as a single word, is an adjective that means commonplace or routine. So, no, you do not brush your teeth everyday. That just doesn’t make sense.

Chronic versus Severe
These two terms are easily confused because both describe extreme medical conditions—but they describe different kinds of medical conditions. Though both severe and chronic conditions are not contagious, ‘severe’ just refers to more extreme, painful versions of common maladies. Chronic conditions must last at least three months, and often last a person’s entire life. Diabetes, asthma, HIV, and cancer are chronic conditions.

Acute versus Severe

Most medical personnel view ‘acute’ as meaning sudden, possibly severe, and requiring immediate medical attention. For example a cut requiring stiches is acute. ‘Severe’ is used to describe to extreme and painful medical conditions which usually require treatment to either cure the malady or comfort the patient.

Magnanimous

‘Magnanimous’ means noble of heart, forgiving, and at times generous. It does not mean large or big. ‘That is a magnanimous building’ is incorrect. It is a magnanimous gesture when someone poor donates all of his money to charity.