Getting Started in Lies of P

Experiment freely with Weapon Assembly early — you can dismantle almost any weapon you find into its Blade and Handle and recombine them, so there's no wrong pickup.
Boss weapons are the exception: they can't be taken apart, but they come with strong built-in movesets as a reward for the fight.
The P-Organ is a flexible passive skill tree — you can choose what to unlock on the fly as long as you have enough Quartz.
Legion Arms like the grappling hook or flamethrower change your stats and add weight, so match the one you equip to your build, not just its gimmick.