I main as Falco, and the first thing I learned is SHFFL L-canceled aerials.
To do those you need to do
(tap) >
OR>>
I play on Melee, btw, and according to your profile you main fox on 64. On 64 there isn't as much tech, but primarily you need to neutral-b-cancel or something like that, which makes you turn in midair (sorry for low detail, I don't play 64 :o). Also, uniquely in 64 when you shine and land it instantly cancels all lag. So whenever you shine on that game, short hop right before.
Back to Melee, practicing wavelanding/wavedashing is good, too. You can wavedash out of shine or shield btw (known as waveshining and waveshielding). On a side note, you can also jump out of either, known as jumpcanceling.
Back to the speed stuff though, learn to laser then fastfall, at the 3 heights. (
>
>
)
Enemy's head: attainable only on the ground I believe.
Middle: shoot earliest in the jump, then fastfall
Low: shot a
very little bit later then middle
Right now I'm working on applying teching when hit (
before tumbling into the ground after being hit)
and applying L-cancelling to ALL aerials.
Always remember these three mainstream Smash tips:
1. practice, practice, practice, practice, practice, practice, practice!
2. (by ssb64 god Isai) Don't get hit.
3. git gud