I want to host a spa party for my 15th birthday, and i need to knwo some of the essentials.

I am allready planning on getting a robe, towel and slippers for guests.

but, i’m not really sure where to start with everything else.

I want to have a spa party with my close friends. Have do I need:

what type of food?
what kind of dessert?
what kind of party favours?
And any other advice you would like to offer.

Thanks for your help!
I mean… WHAT do I need?