First Technique: Wavedashing. All you need to do to wavedash, is press your jump button (x/y) then quickly input a diagonal on the left stick and press L, or R.
Second Technique: L-Canceling To L-Cancel, you need to jump again then input an aerial attack close to the ground then press L or R to reduce the landing lag when you hit the ground.
Last Technique: Fast Falling Fast Falling, or FF, is the easiest. Just jump, and when you are in the air, press down on the left stick, ad you'll fall faster!