I don't like the word 'strong,' because a strong character is never an interesting character. A character is made interesting by their vulnerabilities and their weaknesses.
Two phrases I hate in reference to female characters are 'strong' and 'feisty.' They really annoy me. It's the most condescending thing. You say that about a three-year-old. It infantilises women.
People become more interesting from about 25 - they develop character and their personalities come out.
I've always found as an actress that the best thing to do in film or TV or theater is just to lose yourself in it. Think of the story, the character, the worlds we're in, and forget everything else.
Women are always self-effacing and self-denying. There's a term that enrages me, and I always used to swear that I'd never play characters described that way. The term is "long-suffering."
You know, he [Alan Rickman] played these very reserved, sometimes-cold, sometimes-threatening characters on the screen, but the reality of the man was incredible warmth and humor and generosity and wicked fun.