If I'm going to try a totally new trick(lets say switch 9 for our purpose) on a jump I'm not used to, I usually straight air the jump 1-15 times then warm up all my spins forward and switch, 1,3,5, and 7, then all of those switch before I even attempt the switch 9 because you always have to be able to have a way out if you fuck up. THEN finally it's time to attempt the trick, I usually like a 25-30ft jump for a new spin and just make sure you commit because if you don't there is no way you will land the trick. Once you get it, make sure you do it at least 5-10 more times to get it on lock. Or at least that's what I do.