Kevin Schroeder has a suggestion for developers out there - you should hit F5 more often:
The best developers hit "Refresh"? No. Well, yes, but that's not what I was referring to. F5 is what you hit in Zend Studio/PDT to "Step Into" during a debug session. A LOT of developers just look at an API, or code completion, write to it, commit, deploy and they're done. I have found that the best developers not only build to the API, whatever it is, but also watch the API at work.
In his opinion, he's never met "the smartest PHP developer", someone who couldn't learn something from stepping through someone else's code. You don't even need to fully know what's going on to catch helpful bits of code or new ideas you may not have thought of along the way. He also suggests conferences (like ZendCon) are an excellent place to pick these same things up, just in person.
Having been asked what people can do to become better programmers, I would respond by saying that hitting F5 would be pretty high on my list.