What is some good must-have jewelry?

What's some cute must-have jewelry that I should have in my collection? I kinda want to have some vintage jewelry but I don't know if I can pull it off as my style is rather cute/casual and I build it up from there with accessories if I have time.:) I really like stretchy bracelets and necklaces that you can pull over your head.:) I shop at places like Wet Seal, Kohls, Forever21 and Claires. I'm 20 years old by the way.