Unfortunately to be a good director you have to be brilliant, and have a keen eye for seeing depth in everyday life.. Not many directors are good, in fact, I can't think of many American directors who are good these days (more on an international scale).
In terms of an actor, much of the time the best performances are subtle, and not your "psycho" crazy performances - unless you are Robert De Niro, Klaus Kinski, or Toshiro Mifune.
To be a writer you have to be strong in spelling and grammar, and often the good writers make it seem more like an art than fundamental technique-- again, a very keen eye toward life, society, and culture (but not all writers have to have that- I Hope they Serve Beer in Hell by Tucker Max was hilarious) and "practice" will help, but again you have to be very talented.
A script writer, hard and often script writing courses won't help you in terms of formulating your own style and being different. If you can create a whole script for a 5 hour film solely on the conversations of a married couple (Scenes from a Marriage - Ingmar Bergman 1973) then you will be an amazing screen writer.
I imagine a make-up artist would be the best option.
