I learned two things from watching Nevarra's bow technique vids:
1. The index finger & pinky are the most important fingers ... the pinky is for balance ... it is important to concentrate on both of these fingers.
2. I was doing my bow changes wrong ... I was doing them with the fingers and not with the upper arm ... he had an excellent point: you can tell if you're doing the change motion correctly, because the angle of the tip will remain the same. That was a valuable lesson & I'm playing better already ... coordinating bow changes was always something I had trouble with. ... It's amazing how much of playing the cello well really just comes down to have a concretely & correctly defined technique
Caveat: Anybody reading the above should go watch the actual videos, because it's easy to misunderstand what I'm saying since it's out of context (and I don't think I'm explaining it well):
Part 1 - http://www.youtube.com/watch?v=_ber93Z85eA&feature=related
Part 2 - http://www.youtube.com/watch?v=OiNhZrMhD6I