How to: make a centre pull yarn ball

I love using centre pull yarn balls and rarely seem to have the problems with them that other makers mention, e.g. tangling, pulling out half the ball/a confusing chunk of yarn barf at the start or the outer edge unravelling and twisting round the working yarn.

Here's how I do it:

What do you think: is it my technique or do I perhaps have some kind of magical yarn charming powers?