If you find a way to do something faster then please feel free to share it here.

Green Ranger = Jumping Fire Sword, This is faster to kill most to all enemies because you do not need to wait for his attack to finish.

Yellow, Crimson, Navy Ranger = Use their gun, nuff said, I like to use crimson ranger for his special.

Red and Blue Hawk Rangers = Gun, again, but on the boss charge your special all the way then 2 charge attacks should kill any of them.