Knowledge of the system is huge for me and fluidity when rolling live. Gotta have some tournament experience too. Consistent attendance, application of correct technique down to the little details, implementing a strategy when rolling, guess there are alot of variables involved, but the biggest factor is MAT TIME. There's no replacement for good ole repetition on your go-to moves. John has a good list of grappling fundamentals to serve as a guidline and I agree every blue belt should have those things down. Human beings are exceptional animals in that the more time we spend doing something the better and better we get at it, pretty amazing actually