Acting is a dream . Acting is the work of the imagination. Actor can't pretend things, it has to be emotional experience. Actor should never make yourself comfortable crossing your legs etc. All good acting must look like it was never rehearsed at all.
All work has to be hidden.
Act with your whole person. Art of acting is to move the audience not the actor. Bigger emotions must be more relaxed. Bully look for coward. Bury all the work, conceal work.