I'm a screenwriter, and I to make my female lead stronger. She's about 32 - 38 years old. She's in the middle of a divorce. And this is an indie film so production cannot afford to film her in a business setting. She can't be sexually aggressive. Although possessing a sexual air and/or sexuality in her dialog is fine (although she can't be flirty she's not a teen or a ditz.)
Just thinking about a few nitty gritty details, which would give her character "flesh".:
I think it's important, in the course of the action, that we discover that she possesses a few flaws. That she's not "perfect feminist role model material", in other words.
Perhaps she's made a few personal or business compromises along the way, which she possibly now regrets? Or perhaps those compromises were considered "necessary" (at the time) to achieve her success? Are there repercussions now? Does she have children? (whether we actually see them in the film or not)? How have they been affected by her divorce, and/or her career commitments? Are they a point of contention between her & her estranged husband? Do her children like & respect her? Are they giving her grief (fairly or unfairly) as she tries to get her life on track? And what caused the divorce to occur? Does she have regrets or is this something she's been wanting for a long time & now is the moment?