One tip I can give is activating the extra buttons when you hold down both L2+R2 at the same time.
Depending on whether you press L2 first, then R2 give you access to 8 more abilities. Or, if you press R2 first then L2 that's a whole different 8 abilities.
Although, I have L2+R2 and R2+L2 to show the same hotbar (cross hotbar 3). So in total, I have access to 24 skills rather than the traditional 16.