I assume your not in school studying compostion, or you would have plenty of resources. But, that's okay. My advise would be to go to a local university book store and check out the texts they offer. Don't buy anything there though, just look. Check out half.com or amazon.com. Usually, you'll get a better deal. Or, if your really serious about composition, contact the music department and ask about private composition lesssons. Most professors would be more than happy to offer you out side lessons, but don't quote me on that, they're extremely busy, but sometimes you can get lucky. You'll develop better as a composer if you're guided by a knowledgeable teacher. We use "Tonal Harmony". It's a very good resource, theory from start to finish. Also, check out some basic counterpoint resources. Hope some of this was helpful. Good luck!
