Look up andsel Adams zone system. Even if you have no interest in shooting on film or darkroom work, seeing how a master went about choosing the exact shades of gray for each part of his frame will help you start thinking critically about exposure. As far as framing, subject, and technique go, find photographers whose work you really like, read up on it, and start questioning it. Why did they shoot it that way? Why did they chose to crop the image there?
Sorry I don't have any specific books to recommend off the top of my head, my background is in film and video, not still photography.

oh. woops.
Apologies for image macro

SAGE has been used.

I don't have any background in photography, just throwing out a reddit link, and check their sidebar:
http://www.reddit.com/r/photography/comments/15dq3u/weekly_question_thread_ask_rphotography_anything/

I have an older copy of his darkroom book and it's very informative and detailed. The only problem is that the info gets a bit clusterfucky sometimes. I don't know about this one in terms of digital, but no doubt it's great for film.

It might not be any help anon, considering I learnt photography from various books dating back to the 1970s. I uploaded this for though, it might be help if you wanted to do film photography and develop your own shit later own. http://www.mediafire.com/view/?b9ksfatw38wg8ug

Fundamental of Photo Composition by Paul Common is a very useful book for looking at the artistic aspects of photography separately from the technical camera setting most hand-guides will have. It may be a good place to start.