Practice on a plane that will do them well first of all.....for me, I learned them on a Mojo, Burrito and Primo. Inverted harriers become just like anything else when you have mastered them, you don't have to "think" about the inputs, you just do them as it is burned into your soul. I have worn the covering off more than one rudder top from inverted harrier 8's dragging in the grass! Burn lots of fuel, thats how you'll remember!!