In regards to grammar, which the poster below brought up as well...you should think about reading The Elements of Style By Strunk & White. There's a ton of how to write books out there, but most of them aren't worth the paper they're printed on. This one though is really, really excellent for introducing the fundamentals of grammar and style. I think you'll find it very helpful.

You can read it online here (http://www.bartleby.com/141/).

Don't get overwhelmed. It's a really short book, but it's packed with information.