The vibrato lessons here and elsewhere on the web are not very helpful. There is almost nothing on actually how to practice and build up to a good vibrato technique. Its like showing someone a Van Gough painting and handing them some paint and a brush.

Vibrato, especially for right-handed people involves a slow and steady retraining of the brain. It involves a rapid succession of a bend and relaxation - a very unnatural motion to do more than a couple of times in a row, especially with the non-dominant hand. The push or pull action fights the relaxation that's needed to return the string back to the unbent note. This applies to voice, violin, etc.

So I would like to see a detailed lesson on practicing and working up to a solid vibrato, not just a demo of how it looks once one has mastered it.