When asking a programming question on SO, how much homework (i.e. searching both inside and outside SO, reading materials/books/papers, attempting hacks on own, etc.) should be done prior to posting the question?

The reason why I'm asking is that I asked a question and got a great answer, but at the bottom of the answer, the answerer cautioned me on doing my homework first (i.e. - attempting to find the answer on my own). I thought that SO would be a great place to start my learning curve. Should I not start with stackoverflow, or should I just use stackoverflow when I can't find the answer anywhere else?