Wavelanding, multishining, and ledgedashing if you don't know them. Foxtrotting, but people really don't use it. Shield dropping and Isai dropping are good to know. Make sure you can RAR. I assume you can wavedash because you can waveshine. Start teching everything if you're not. Ledge teching is helpful to learn, too. Make sure you can wall jump to aid your recovery. You probably want to practice SHL FF, in addition to SHDL. Being really comfortable powershielding is helpful against projectile heavy characters and especially Falco. Illusion shortening is pretty important, too. Remember to do JC grabs, not dashing grabs. Remember that SHFFL timings are different when you actually hit someone, especially dair. You could learn to moonwalk, though I don't think Fox has any practical applications for it. DI is very important. SDI is also important (especially if you want to ledge tech), and dual stick SDI is superior to SDI when getting out of rapid jabs, etc.
Sorry it's so jumbled. I probably missed something, too.
Also you kind of have to relearn Fox in Melee. Having PM Fox down is really, really helpful, but you still have to learn everything again, plus JC usmash, and you have to get used to not RARing.
