I found this blog post from TheProbalist.com.  Enjoy and don’t hold me to its standard…

Ok, so technically the following words aren’t misspelled. They’re misused. The reason you should review this list is because a spell checker won’t correct these for you. Make sure that you’ve got foolproof control over them (especially if you tend to write around 3:12 AM like I am now). Extensively misusing them throughout your posts may actually cost you a visitor or two every now and then because some folks do get caught up on these, which means they won’t focus 100 % of their attention on your incredibly valuable content!

1. Your – You’re
As mentioned above, your message might lose impact if you’re not paying attention to this number one word maltreatment. If you find it particularly difficult to separate them from each other, stop using ‘you’re’ altogether and notice how you are starting to improve your spelling.

2. Then – Than
The next step is then to tell yourself that it’s better late than never to get that vowel placement in order. Then your readers might find something more useful to comment on than your apparent spelling impediment.

3. Its – it’s
It’s best to write an article and its words properly for optimal reader engagement. Again, if you still fail to tell the difference without effort, just write how great it is not having to worry about misusing or misspelling words.

4. To – Too – Two
To write two posts per day, or not to write two posts per day. That too is the question.

5. Were – Where – We’re
Where in the world were you? We were at Billy’s and we’re staying for another day. Make sure your blog visitors do that too.

6. There – Their – They’re
They’re moving their cursor over there. By focusing more attention on proper word use, your visitors won’t highlight and pinpoint your mistakes.

7. A – An – And
A flawlessly written article serves as an eye-opener and should provide lasting value. Remember also that an abbreviation like SUV starts with a vowel pronunciation and requires an ‘an’ in front of it.

8. Off – Of
Of all the mistakes you could prevent from appearing, start off by checking out this common mix up. You should have paid attention at school when they told you not to write ’should of’. Or off your visitors go.

9. Here – Hear
Hear ye! Hear ye! Here is a blog worth reading. You can almost hear the distant clicks of new visitors finding their way over here this very moment.

10. Lose – Loose
But if you’re too loose on your writing discipline, you will end up losing those readers after a while. You’d have a bolt loose if you don’t apply these 10 writing rules from now on with greater care. You win some and you don’t lose anyone.