The Inspiration for Rachel Berry

Though sharing many characteristics with TV Rachel, TTM Rachel Berry is more timid, less control-freak, but equally as hopeful and hungry for stardom. I figured that in the 20's a woman of Rachel's economic and social standards would have been somewhat oppressed and therefore more subdued, with not as many opportunities as today's Rachel would have.
 Behold, Rachel's muse, Ms. Fanny Brice.
Just as TV Rachel worships the woman who played her in an Oscar-winning role (the irreplacable Barbra), 20's Rach reveres the real thing. Fanny and Rachel share similar beginnings, which is why she looks up to her so much.

This picture is what basically served as an outline for Rachel's character. Hopeful, starry-eyed, wishing for something better than what she has.
So in some ways, the two Rachels are different: TTM Rachel is far more subdued and less high-maintenance- she's never had glamorous opportunites or beheld as a talented star, much unlike TV Rachel.
But they're similar in their tenacity, strength, and will to do anything to become a big star.