This issue may seem small to you, but it really gets on my nerves (I'm guessing it does to plenty of other people, too). I'll keep this short and sweet:
THAN - think amounts (and comparisons)
THEN - think time (and order)
I ate more ice cream THAN you did. She is sweeter THAN her brother.
I went to the movies, and THEN I met him for dinner.
Also, I'm thinking about either putting some of my poetry on this site or starting another for my poetry - any comments?
Update: I started a blog for my poetry (free to view, but feel free to click on an ad). The address is http://emsbookofpoetry.blogspot.com.
If you ever have any grammar questions, leave a comment! If you leave your e-mail address, I can get back to you immediately. If you would rather not share your e-mail, I can put the answer to your question up here on the site. You can also leave me feedback about the posts I already have up, or you can make suggestions for posts that you would like to see on my site.
I also am available to proofread anything. :)