Seconded.

I find that the thing to focus on is the vertical roundness at the beginning, and then focus on the side-to-side.

Also: take your time, and don't be afraid to put all the kit down and go and do something else for a while. I spent almost a week on my first wheel, doing a half-hour a night. But then I have a fantastically short attention span. The next one took 2 evenings.