I'm stuck with a roleplaying problem. I'm building a character for a potential game, and the GM has stated that the characters need to be well-written, so I'm trying to develop a good backstory and believable personality for my character.

The problem is I have no idea where to go for either. I can't even decide what kind of alignment this character should have, as I'm moving out of my comfort zone of Lawful Good religious types.

I have the character's statistics all figured out: She's a human sorcerer with the Serpentine bloodline (the game's Pathfinder), but that's all I have figured out. I'm drawing a blank on what she's like as a person and what her story is. I'll admit a certain bit of escapism, but I don't want her to be just a cheesecake character. I want to be something other than Lawful Good, but don't really know how to roleplay anything else believably. I've got some basics for the very end of her backstory, that she's booked passage on the ship the party will start on, but nothing about her origins, her parents or her education.

What do I do?!