After learning fairly everything about formatting -- which seems to evolve almost yearly -- the most difficult thing for me is resisting using too many parentheticals to guide the reader and the actor and the director what emotion you intend. For example (angry) (non plussed) (overjoyed) etc. It all boils down to the mantra drilled into screenwriters -- "Don't direct the script! Let the actor interpret or it's the job of the director to instruct the actor." But sometimes a parenthetical to indicate the emotion the character is feeling is essential. Are they hiding their emotions? Are they exposing an emotional truth that reveals something to an accuser that gives them away leading to a future action? Usually the context of the scene dictates what the character should be feeling but not always. But man, the urge is always there for writers to convey the exact emotion the character SHOULD be feeling and all screenwriting software has that parenthetical option. I have learned to use it as sparingly as possible. My earlier scripts were loaded with them.