One thing you can do is try chaining FAIRs across FD and ending in DAIR. 0 - death. You'll need to master 2x SH FAIR first.
The spacing is different at different percentages and depending on the character's weight/falling speed. On semi-floaties to average weight characters you should hit with a sweet-spotted FAIR or possibly two, until the character is a good bit above you. Then you can easily hit with regular FAIRs across the stage, ending with a sweet-spotted FAIR to DJ DAIR.
Can also practice chainthrowing Fox/Falco, catching them in u-tilt chains, punishing with tippers when they try to leave the u-tilt chain, and starting u-tilt chains from sweet-spotted dash attacks.
Do this against Lvl 1 cpus. Anything higher will potentially mess you up against humans.