I'd love to see something that discusses each layout parameter, both in QtCreator and from code (e.g, setting sizeHint in QtCreator is done using several other parameters (I think)).

Some have recommended purchasing a book that supposed to have a good explanation--I'd have to track down the name again. But, it was qt4 and I don't know how much has changed since then.

I always get something working, close to what I want, but it's very empirical. Tweak, try again until I get something like I want.