[astral303]

Read "Clean Code" by Robert C Martin. It's Java-centric, but very applicable nonetheless. It's a compilation of years of insight about how to design your programs, and it explains well why you should care about writing your code one way or another. It's the first time ever that I have seen an illustration of violating Demeter's Law that was actually believable and the proposed solution deeply communicated the intent of the law.

The book progresses from smaller details (like code formatting style) to very large concepts, gets very deep towards the end, so don't be afraid if you get lost a third of the way in. Just leave it and come back to it as you gain experience.