I'm going to disregard the million other threads on this, and the thread on DnD's site where one of the twins (I think dan) leaves a page's description of tips and just say this
Practice.
Lets stop making these threads. People leave you answers, but it's stuff you need to figure out by yourself in practice.
That being said: make the transition of the Thumb and index to the ring and index, and then spin with the index and middle as fast as it can be. Make sure that it lands very square. messy ones are bad.
The rev cut rarely ends up looking like it does on the system in fast speed. DnD do not do it like that in public, or even on the trilogy. The cuts were reshot until they were done absolutely perfectly for the fast speed, so don't be discouraged by their Rev cuts.