I definitely wouldn't knit more than 2-3 per person.You can fold them into quarters and tie with ribbon just as is without wrapping paper.
I liked this very simple waffle knit dishcloth
For teen girls, I'd say it depends on their taste. I find that all of my friends(18-late 20s) start making cute overload squeaky noises when I show them my amigurumi
(crochet).Another simple gift for a coffee lover could be a mug cozie
. You could even maybe make some simple headbands
I get flooded with requests every time I take on a new craft; sewing, corsetry and knitting have been the worst. O__O people actually wanted me to make dozens of corsets for everyone
.I now only make the more complicated things for pay.I do give gifts but I don't say yes to requests anymore.I took these things up for my
benefit,after all- lol! Remember that it is your craft and if you feel over loaded with the workload, you can always say no.