Featuring Jane Wyman in "Johnny Belinda".
Play a character who has a disability.
Or better yet two.
Be kind to everyone and smile like a saint.
Have a baby out of wedlock.
Better yet if the baby was conceived from a violent, but secret rape from the town villain.
Go to trial for killing a man.
Even better if your disability makes it impossible for you to defend yourself and your life hangs by a thread throughout the film's last ten minutes.
It also helps if the actress has just undergone a personal tragedy of her own and needs to feel embraced by her peers (see Ronald Reagan divorce and death of infant daughter).
(Gotta love how Lars von Trier plays with this cliché concept in "Dancer in the Dark", the man's a genius...)