It's ok. I'll post a list of some ways to help specifically.
Run it through a spellchecker.
http://www.spellcheck.net/ will work great.
Remember the difference between homophones.
"Your" means that you are referring to something that belongs to someone. "Your sprite" or "Your program".
"You're" means you are. It's easy to remember because of the apostrophe. "You're going to need to" and such.
"It's" means It is. Its is possesive. Remember "his, hers, and its".
Some mistakes on the site that I've already fixed are "Draw's" and "give's". Unless it belongs to someone named Draw or give, this should have been "Draws" and "gives".
I'll post more common mistakes when I see them.