Back in Agent Query Connect, I once posted about ten common writing mistakes spell check doesn't catch for you. The original article came from Yahoo Shine and you can see it here.  If you don't want to click on the link, here's the lowdown, plus a few more that I've seen in some writing:

You may laugh at this and think you're not that stupid, but trust me, even the best of us fall victim to our blind trust in spell check.

1. ITS versus IT'S

IT'S, with the apostrophe, is a contraction of "It is". ITS refers to possession.
e.g. It's a nice day today. (It is a nice day today.)
      The fairy spread its wings.

2. SALES versus SAILS

3. AFFECT versus EFFECT

This is misused more often than not. Affect is a verb, as in: The weather affected her mood today. Though there would be others who'd say Affect can be a noun, such as in psychiatry when it is defined as: A feeling or subjective experience accompanying a thought or action or occurring in response to a stimulus.

Unless you're writing a thesis on Psychology/Psychiatry, Affect stands as a verb and means to have an effect upon; to act physically on.

Effect is usually a noun, defined as a phenomenon that follows and is caused by some previous phenomenon; an outward appearance; an impression (especially one that is artificial or contrived); or the central meaning or theme of a speech or literary work.

e.g. The effects of the drug were hallucinogenic.
       The magnetic effect was greater when the rod was lengthwise.
       His shouting and drunken revelry were all for effect.
      
Effect can also be a verb, meaning to produce, or to act so as to bring into existence.

e.g. Her valiant recycling efforts effected a change in their lifestyle.

If you arm yourself with their proper definitions, you won't confuse the two ever again.

4. WOULD HAVE not WOULD OF

Because WOULD HAVE gets shortened to WOULD'VE at times, people mistake this as WOULD OF (probably because they sound the same). WOULD OF is never correct, and unless you want to be seen as illiterate, do not use it ever.

5. THROUGH versus THREW

Again with the homophone. Two very different words sounding the same. Always double-check.

6. THEN versus THAN

You know this, right? You've got to know the difference between the two. THAN refers to a comparison, while THEN refers to a subsequent event.

7. SUPPOSED TO not SUPPOSE TO

8. WONDER versus WANDER

9. THEIR versus THEY'RE versus THERE

I see this a lot. Sometimes it stems from honest typos, sometimes from carelessness. Proofread your work. THEY'RE is a contraction for THEY ARE. THEIR is possessive. THERE refers to distance.

10. FARTHER versus FURTHER

FARTHER is physical distance. e.g. Farther down the road...

FURTHER is metaphorical distance. e.g. He went further in his efforts to win her affection.

11. HERE and HEAR

Blame it on homophones.

12. WERE and WE'RE

WE'RE is a contraction of WE ARE.

WERE is a 'to be' verb. (ARE/WERE)


What other errors do you find yourself stumbling on occasion?