In my opinion you have to start with cross-matw nt, when you have done this a couple of times (15 times er something) you will see that you gets faster. Now you have to improve your matw, this trick must be done really fast and high so first you have to practise this trick till you can do this trick fast and high.
Question: isn't it easier to begin with tatw-matw nt instead of matw-matw nt because when you do tatw-matw nt you can faster around the ball?
Succes!