Jodie Foster had some interesting things about acting and how she was directed when she was a kid that might be helpful.
She basically said that her previous directors had instructed herto be "be natural" or "be herself" but that sort of thing never really helped her. Her life as an actor changed when she worked with Robert DeNiro on Taxi Driver.
I think you can see that in her work, her acting after Taxi Driver is far better than it was before that film.
I don't know if this short clip will help you, but I liked that interview a lot and this thread made me think of it... I hope it's helpful.