"witch" is just a label really, no one can make you one. [granted it was believed only a witch can initiate a new witch] read and study because a witch typically is someone who is always pursuing knowledge. you can cast spells, but it's not something exclusive to witches. read the basics on magick and the holidays, but since i don't know what path you're interested in, i can't suggest books, but try books by Raymond Buckland or Scott Cunningham.
that website has more information for Wicca, but it has a lot of information on other paths as well, so it should be of some help.