Another useful tip to keep in mind: the aerial landing mechanics of FP.
Unlike aerial A moves, which undergo landing lag if you land during the attack, landing with Force Palm transitions the move completely seamlessly from the aerial version to the grounded version. So it can be useful to use when landing, especially for spacing at higher aura buildup.
Seems like obvious old news to most of us I'm sure, but I did notice something else earlier during some practice matches, and decided to test it out:
If Luicario starts a Force Palm in the air, hits the ground before the command-grab frame, and the opponent is within the move's grab range at the time, it will become a command-grab. Force Palm is that seamless in its aerial-grounded transition.
It's not much, but when in the air against a shielding opponent, they are quite often deliberately baiting an aerial move that they plan to punish with an out-of-shield option or grab. Landing FP grab gives Lucario a way in: a way, if timed well and the opponent isn't expecting it, to land practically on top of a shielding opponent and punish with FP grab.
Also at higher percentages, when FP flames become great spacing tools, I've had some success using it in the air vs. very air-happy opponents.