Before I switched to the rehair tool, I would cut my hair to length (well a little longer than, so I had some wiggle room) and tied a bunch of the knots before starting. Then I'd stop when I ran out of already tied knots, and do a bunch more. This was for ponies, not dolls, but the idea is all the same I'm sure.
Once you've got the head ready for the hair, I think you could do it in any manner that suits your workstyle, really. Whatever makes the most sense for you. There's not a lot of prepwork needed unless you want to organize it in a particular way.