Realize when you're not fastfalling and fastfall everything (not in tournament, but for speed practice, yes).
Obviously L-cancel everything.
Practice dashing out of stun/lag/L-cancel immediately. Watch your character closely as you do this, over and over until you can respond to specific visual cues which allow you to dash or jump (or wd) as soon as you possibly can. It'll come with practice, you won't even realize you're doing it at first. You'll just see that you're faster.
Practice shield drops and running shield (shai) drops.
Practice wavelands! This is huge. Watch how well wobbles wavelands and how useful he makes them.
Practice dash dancing immediately out of wavedashes and wavelands.
Practice ledgedash (ledgehop waveland onto from ledge) and reacting quickly out of it.
Practice edge cancels and various applications thereof (immediate jumps afterward, fastfalls into wavelands, aerials).
Practice true pivots (1-frame turnaround, known as a smash turn) and reacting immediately (like jumping). You can pivot into jabs, tilts, dash attacks, and jumps/aerials. Here's how you pivot bair out of dash as quickly as possible:
![Gamecube Joystick Right :GCR: :GCR:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(DASH)
![Gamecube Joystick Left :GCL: :GCL:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(Actual Pivot) Go all the way to the notch, then immediately....
![Gamecube Joystick Down-Left :GCDL: :GCDL:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(finishes pivot) then.....
![Gamecube X :GCX: :GCX:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
+
![Gamecube Joystick Right :GCR: :GCR:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(Analog jump for approaching bair)
![Gamecube A :GCA: :GCA:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(BAIR) easier than c-stick.
Optional
![Gamecube Joystick Left :GCL: :GCL:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
to commit less with the bair
![Gamecube Joystick Down :GCD: :GCD:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
(fastfall) for auto cancel and hitting short characters. This is crucial.
^^ if you do this correctly (gravy method) you'll have another great tool for your neutral in dittos. But really any matchup. It works so well. Once you get it right it's so fast you can't even see the turn really.
There are lots of other character specific things (NIL aka No-impact lands come to mind and some characters can hardly ledgedash) but that'll get anyone started on the path to bring fast with their character.