Quick focusing is a skill set like any other. You set up a procedure that you always follow, I set my lens to infinity, then practice a lot. The real trick is not to fiddle focus.
What is fiddle focusing? It is sawing the focus back and forth like you were, well fiddling. The method to use is move the focus until it is in focus, and stop! With a RF, fiddle focusing probably only wastes time, with a SLR your eye is trying to adjust too, and you simply can not get an exact focus because there are too many variables.
As Kai showed in the video, you can pretty much match a good autofocus system for speed, and beat it for accuracy.
Additional speed can come because you can already be moving the focus as you bring the camera to your eye. As you lower the camera simply move the focus back to your start point, and you are ready for your next grab shot.