You'll want to know what her best safe pokes are as well.
That being P, 3KP, 9K, 8P, 6P, and while not a poke, 7H+K is phenomenal.
Also you'll want to let go of any reservations you may have when it comes to throwing. If you're not throwing with Pai, you're missing out on a lot of damage and set-ups.
Also keep in mind that you will have to be creative with her. She needs a lot of hits in most cases to reach max stun for a CB, and she is the weakest character in the game, so for damage you'll need to do a lot of combos/throws.
2P is great to cut into an opponent's offense, and if it stuns, she can usually follow it up with P for a continued stun.
Know what's guaranteed with her and what's not. Some of her counters guarantee certain combos, as well as some throws. You can always risk the guaranteed strings for more unconventional mix-ups to get a lot of damage, but that's for you to decide when to do it. It always helps to know what you can do for free, though, especially when the opponent is low on health.
And remember her new hair. That's one of the most important parts. As Destructionbomb would say, #SupportThePai