Form Shift is you're prepull, so you can start with Dragon Kick, which grants a buff called "Leaden Fist" that boosts Bootshine's potency by 100. Before 50, Perfect Balance is an in combat oGCD that just lets you use any of your six GCDs with no restriction, though it's common to alternate Bootshine and Dragonkick (depending on whether you had Leaden Fist going into Perfect Balance).

At 60, you get a new skill called Masterful Blitz. Using attacks under Perfect Balance grants you a "Beast Chakra" relevant to the attack (so Opo-Opo form attacks grant Opo-Opo chackra, Raptor form attacks grant Raptor Chakra, Coeurl form attacks grant Coeurl form chakra). Get three beast chakra, and Masterful Blitz becomes a new, 4th GCD (with AoE fall off) in your 3 step combo. Hitting that 4th GCD also grants formless fist, letting you get back into the flow from where ever you left off or need to.

To go even further into detail, you can't just use the Perfect Balance stacks at random. There's method to the madness. Using Perfect Balance and Masterful blitz with 3 different beast chakra (order you get them doesn't matter) grants you a "Solar Nadi". Using Masterful Blitz with all three beast chakra being the same type (so all three are Opo-Opo), grants you a "Lunar Nadi". Usiong Masterful Blitz with only 2 types of chakra (so 2 Opo-Opo 1 Raptor) uses a weaker attack, and give you the Nadi you don't have (defaults to Lunar). Since the other Blitzs are stronger, you don't want this one. Using Masterful Blitz with both Nadi grants access to an even stronger GCD, Tornado Kick (which is itself upgraded at 90).