Aw lol I would love to help out, but there's a pretty wide range of ideas for this RP. Because ofthe that, I'm not sure what areas need to be filled in.

You could be my long lost half-sister? Haha I'm not sure how to help ya. Sometimes I search foe a picture I like and then build a character off of that, usually helps me get some inspiration, but you can also be vague for now and build up more on your character in gameplay.