Try to hover without any mix on at first. I think it'll be easier to learn that way.

Enter the hover with little or no power. Dive the plane then pull it up with low power. As the plane comes to a stop in the vertical position try to catch it there with power. You'll figure out fast just how much to add. Then use rudder and elevator to keep the tail under the nose. Its kinda like balancing a broomstick on you hand.
If there is any wind, enter the hover while flying downwind. this will help keep the wings steady as its hovering. The wind will be on top of the wings pushing the plane belly first....

It takes a lot of time and practice but you'll get it eventually.