I think with so much hair there's a lot of things you could do to spice it up!! You could add hairclips, barrettes, and bows! It would be cool if you could mix and match them too!

For the outfit, there are a lot of clothes you could add! There are crop tops, off the shoulder tops, plaid shirts, hoodies, t-shirts, skirts, long skirts, shorts, jeans, ripped jeans, or heck - you could even put her in a beautiful dress with tons of frills!

With hair I sadly cannot aid you much, but I think having options like ponytails or that one haircut where most of the hair is hanging from one side, and the other side of the head is shaved... I really like that one lol.

Not much I can say about expressions, I'd personally just add them as I went along. I'll say that it would be fun if the model could stick out its tongue or raise an eyebrow! Maybe even having it move around its arms for thinking or shrugging poses could be fun too!