I went to Coachella this year and I brought one pair of high waist ed shorts, one skirt and the rest dresses. When wearing dresses I would suggest getting some bootie shorts to wear under them to prevent your thighs rubbing together and chaffing! Get a couple of pairs because they will be sweaty and disgusting after each day. These are the outfits I brought, shoes.

My sandals were only worn for kicking around the campsite and the thongs for showering in. Not sure if you are camping or not. I think for kicking around the festival my Toms and Keds were the best, comfortable, and kept my feet from getting too dirty. My moccasins were comfy, but since my feet were sweating sooo much the colour transferred onto my feet. If you do bring Toms/Keds get the odor inserts that Dr. Scholls makes, so that your feet aren't super stinky and maybe even some "not-socks".

I saw a lot of girls wearing boots, but I don't know how they could handle it in that heat. It was so freaking hot, not sure how warm Bonnaroo will be. I have heard it is quite a bit dirtier than Coachella.

I would also suggest getting a hat to bring to protect you from the sun, but please don't get a big floppy hat. I find them really annoying when you are trying to watch shows.. My friends kept falling over her face too and she had trouble seeing. :-(

For a purse I brought in an over the shoulder bag with the bare necessities inside. Money, ID, SPF chapstick, sunscreen, camera, water bottle, and a light scarf to cover up my shoulders from the sun. Sometimes it was also really nice to run it under water and rest it along my neck.

I can't think of anything else, so I hope that helps. Have fun!