As others have said, a sim is key.

When transitioning to "real life" I found that getting a plane that does NOT drop the tail when doing an inverted harrier is a big help. Much depends on trim, however some designs are better than others.

I've had real good experience flying the Accel Hobbies (now Value Hobby) Cap 35 ES designed by Gary Caruso. With a A20-20L it's a great light and relatively durable plane that makes an excellent inverted harrier "trainer". Batt is any 1300 3S size.

http://www.valuehobby.com/product_de...d=4&item_id=38

I'm sure there are other good choices, but that's one which I know works well while learning inverted. Gary purposely designed it to NOT drop the tail which is one less thing to worry about (balancing the throttle with the airspeed/elevator input required) so it makes it just that easier to learn steering.

The plane has very little coupling also (great KEs) so it's a fun one to 3D while not training.