It is good to practice punishing certain situations with 720 to get the feel for it. For example, learn to buffer it during a Voltic Charge, to simulate a burst bait punish. Set the opponent to Burst your 5C in training mode. Special cancel the 5C into Voltic Charge to eat the burst, then 720. Classic!
Try also doing it on whiffed moves so you can sneak in a 720 when your opponent doesnt expect it. A good example would be, 5A > 5B > 2B (whiff) > 720 after Gadget Finger. Buffer it during the pressure and time it so you do not accidently jump cancel the 5B. Make sure with all of these, mix it up with Atomic Collider to grab people who up back.