Having built about a dozen wheels over the years, I thought the WheelPro book was worth buying to see if I could improve my technique any. Loads and loads of info in there, but not much I didn’t already know about the basics.
However, the single most useful piece of information I gleaned from the book was the following, and it’s always worth bearing in mind when things aren’t going your way: if the rim starts out round and straight (which it bloody well should if it’s new) then if it’s no longer straight and round then there must be an imbalance in the spoke tension somewhere.
It sounds really obvious put like that, but it changed the way I think about building a wheel.