Buttons are down in generic term, seeing as there are so many control schemes out there.

Down
Pressing down will make Pit duck. No other explanation needed. Pit is slightly taller than some, so even ducking won't save you from some attacks. Pit cannot crawl.


Smash Button
Pit swipes up to three times at his opponent. Easy to say that this is the most standard type of attack Pit has, but still causes a fair amount of damage if used correctly.


'Grab' Button
Literally, Pit grabs his foes by the neck roughly. He either slams them behind him, or knees them in the privates (Ouch) before throwing them away.


Left/Right + Smash Button
Pit charges his Smash attack, then lets it loose by swiping rapidly. A powerful attack, even when it's not fully charged, and easy (and quick) to use in battle.


Special Button (+ Directional)
Pit's main special move is his arrow. You can charge it up, then fire whichever way you want. You can change to left, right and down, and, once fired, can change the arrows direction.


Jump Button (Hold down)
Pit is one of the only 3 characters that can glide. Jump up and hold the jump button down and Pit with glide forward. Be careful, you can easily glide off the stage if you go too far, and it counts as your special. Pit can still descend by pointing him up or down.

Glide (Or just jump) & Smash Button
When gliding (or jumping), Pit can still attack - Press the Smash Button and Pit will instantly swipe his opponent in mid-air. Handy when someone plans on taking you by surprise.


Jump Button
If there's one thing Pit does best, it's jumping. He can jump around 3 times before his wings give out. If you still need that extra leap, there's always gliding and his special, too.


Down + Special Button
Pit can use his shield to block just about anything aiming at it. If a projectile hits it, it will rebound off and Pit will call out. You can move the shield slightly above his head.


Up + Smash Button
Another powerful attack, especially if it hits correctly. Pit will rapidly slash his bow over his head, smashing anyone nearby with a lot of force.


Up + Smash Button
Pit throws his bow into the ground and kicks his legs up in the air to smash anyone out of his way, before safely landing on his feet again.


Up + Special Button
Pit is one of the best characters in the game where recovery is concerned. Pit uses the Wings of Icarus to fly temporarily. Watch out, he takes a while to activate it properly.


Down + Smash Button
Pit swipes back and forth rapidly on the floor beneath him, tripping any foes that dare get too close to him.


Special Button
Pit rapidly spins his bow around in a circle. Enemies can only blast through it with extreme power, and it's very hard to get out of, unless you jump over his head.


Special Button (Once Smash ball is active)
Once Pit has the Smash Ball, he can summon Palutena's Army to help him. Centurions will fly from all angles at the opponent, each one causing hefty damage to the enemy.