I have a butterfly knife, I know alot of tricks, default spy opening knife, Zen Rollover(Meet the spy), TF2 Beta Balisong draw.
Look on youtube to learn stuff.
I recommend actually taping your knife first, don't use a glove because you wont be able to use it.
With aerials, TAPE THE KNIFE IF YOU DON'T WANT A KNIFE IN YOUR HEAD, all over, even on the blunt side.