What to get a thirteen-year-old girl for Christmas?

If she likes doing crafts, a gift card to Hobby Lobby or a similar store. If she likes movies, a Fandango gift card. Or, one of the prepaid Visa type gift cards could be used anywhere, to buy anything, even online. 

Take her shopping at a mall, and let her select her own gift.

Check and see if she has an amazon wish list. Even if you don't buy anything from it it's a clue what she's into and/or ask her mom. 13 is a borderline age. She might still be into some kid stuff at that age but be so over other stuff. At that age I loved getting proper art supplies because I couldn't afford nice watercolor paper and stuff like that, but I was arty,

You ask her directly for  wish list or your parents. If there isn't some sort of a beef with the family i would suggest making the time to see her more and such. Down the road, you may regret not but I do understand. These things happen.

I feel like saying "a thirteen -- year -- old boy" . "Dear Abby" said "Money is always the right color, the right size, and it always right in the wallet !" . My brother used to ask me "What do you want for Christmas ?", so you could ask her . I always buy two presents for my friend's niece, and I never ask her what she wants . I'll buy her something with the word "Princess" on it, or a frog figurine . One time I bought her a T -- shirt with an angel printed on the front . For the past few years, I've been getting her DVDs of a movie she might like . Good luck, and I hope this helps .

You sound like an annoying. Mom!!! !Buy her a gift certificate
At a mall...

I would get her a card that says she is a wonderful sister, and I had difficulty finding a gift that was as wonderful as she, so I got her a Amazon Gift Certificate. Don't expect her to get excited over it, but she will be able to get something she really likes. 

Ask her for a Wish List, maybe 3 things.   Give her a price point. (nothing over $20 for example).   Then,buy what you want off the list- she'll get things she wants and you'll be a happy brother.  

Maybe an Mp4 player & a tunes card?

Maybe some money? Or a book? Gift card maybe?

Ask her to make a "wish list" on Amazon.com
and then you can choose from that list.

When I was 14 I got a set of Acrylic paints. They have suck in my memory. Or perhaps another craft item?
Or get her a gift card for a certain store.
You may also Pray to GOD about this. 

Perhaps a Lego set? I’d suggest a set from Lego friends, Lego Disney or Lego City. 

Get her a 2019 Mercedes Benz so when she is 16 it is all ready for her and in the meantime you can driver her places. This way she is spoiled and can become a narcissist when she grows up like Donald Trump or my sister.