The most valuable thing in software is knowledge. That comes either from experience (slow and painful, the jagged little pill), from other people (if you're lucky enough to have a local expert, I often don't) and from books/docs (easily available, if a little time-consuming to read). I go straight for the docs. They give the biggest ROI I can easily get my hands on. Really knowing your tools gives you a lot of power and it's a shame people don't seem willing to spend time on them.