I go straight up and if I want it inverted I will give right rudder,kill throttle and hammerhead down releasing rudder and give left aileron let it spin a couple of times then move the right stick to the left corner and give right rudder at the sametime. while slowly adding a little throttle ( not too much just enough to keep it spinning) when i add the throttle I slowly take away some aileron (moving it twards center) untill it becomes flat (all of my models become flat in a different area on the aileron removal. some have to go a little bit opposite aileron) keep the elevator full down rudder full right.. You can keep it in the spin if it is a plane that will not lock by transitioning between power and aileron removal or opposite addition... most planes will lock in the spin when it becomes flat..... also watch out I have had some planes that will lock so hard that the only way to get out is with throttle... I dead sticked one such plane in a flat spin. A Sig Smith miniplane. It never came out because i didnt have any power to get the air back accross the control surfaces. It flat spinned all the way to the ground destroying the plane... 3D planes have more control authority. I havent found one yet that would lock like that..