This is where my thoughts are:
The rainbow loom thing with the little rubber bands
What are you ideas?
My daughter likes socks from www.littlemissmatched.com . She has to follow a strict dress code for school (khaki or black pants, collared shirts in specific colors) so socks are a way to express herself.
Her big gift this year will be an ipod touch, which I'm aware people have mixed opinions about for a tween.
The socks sound really lovely.
One thing that helps is to frame the way Christmas will play out. If there isn't a lot of money (and at our house, that is a year-by-year thing) it is good to address it in the weeks before. Little comments help kids modify their expectations.
For pre-teen girls, I would suggest clothing, movie passes, tickets for future events, and crafts. Games are good as well, especially board games. It's important to have a gift that can be opened and used right away.
If you have older people over for Christmas, it's fun to play a board game, but make sure it is within their cognitive limits. Sometimes it's nice if the child is given the game or craft but knows that it is meant for playing with Grandma while the turkey is cooking.
As for clothing, make sure it can be exchanged. If it is all perfect, pat yourself on the back. If it isn't, arrange a date to exchange it together, and to discuss style choices.
I am studying to be an art teacher and am an artist of sorts myself. One of my peeves with kids art is that they tend to be given some of the worst supplies to experiment with. Talk about taking the fun out of things! I suggest some really wonderful high-end art supplies. There are beautiful water based crayons for instance (they come as singles and have the most amazing range of colors...and are very expensive). Or markers (from the fine-arts store). There are nice paint markers but also a great selection of ink markers in a great range of colors. Then some great papers - nice paper makes all the difference. If you really want to get into it (and don't mind the chemicals) I'd consider oil paints and an easel (that's what we are going to try to get for our DC this year). There are even now water soluble oils, which I'd kind of like to try myself.
Keeping in mind of course that art supplies can often be some of the least healthy things a person can be exposed to.
DC has a Rainbow loom and it gets a lot of use in our house. Fair warning - those rubber bands get everywhere.
There are also some great board games for this age. DC loves Settlers of Catan and things like that.
A musical instrument? Guitar? I'm a snob about that too in that I think if you can swing it a quality instrument is the way to go. Some of the big guitar makers have a 3/4 guitar (travel guitar) that would be a beautiful (and expensive) gift for a kid this age.