Underused, and most viable ways of damage rackup:
u-smash
d-tilt
n-air
d-air
More favorable and easier to hit damage rackers (but best saved):
f-air
u-air (YES!!!)
forward Smash (jesus christ this move...)
d-smash (and this, come on, it's one of his fastest kill moves!)
Bread and butter damage rackers:
Arrows
throws/pummels
forward B
mirror shield (yes, for projectile wars, this does good damage)
THE KILL MOVE:
bair... seriously. Save this ******* until high percents or only use it for racking up from 0~10 percent. It's so hard to NOT whiff.
Start off the match using easier to hit and bread and butter moves, and then rack up damage with your underrated moves, finally leading into your easier to hit kill moves
That's a generally good strat to keep from begin->middle->end percents.