The way you play the neutral with Pit is like this. Throw out a jab to make them shield. If they shield again, then you can go for a dash grab and go for your basic bread and butter combos (dthrow to usmash). If your ever not sure of what your opponent is going to do, go for some fast fall empty hops, or dash shield to see what your opponent will do and play it accordingly.
When they are in high percentage (70-90%), save your fthrow until they are in kill percentage (120% or higher). Same goes for the side B. Pits realistic kill options are fsmash, usmash, side B, and fsmash.
Pits roll comes out far and fast. The purpose to roll with Pit sometimes to regain stage control, or trying to go through rapid jabs and punish them on the spot.
When your hanging on the ledge, there are multiple ways to mixup your recovery. You can do a drop down off the ledge to do a rising fair, or do a rising Dair to ensure safety and mix up the landings, so you can land safely.
Pit is a character that can play in two ways. If your hyper aggressive, watch Nairo and Kappamaki, or if your a patient player, then you may want to play the bait-punish game (Chompy, and Earth).
Here's an article I wrote a while back talking about the bait and punish game.
How to Play the Bait/Punish game with Dark Pit/Pit