I've worked MANY summer festivals in my time. Ozzfest, Lollapalooza, Download Fest, Mayhem, Warped Tour, Outside Lands, countless blues, soul, and jazz festivals, radio station festivals, and many, many others. One thing I advise you to do is to bring a bucket of sunscreen and a barrel of water. In the 10 years I've been doing summer festivals I would say that 85% of the people that have needed Rock Med have been cases of sun stroke and heat exhaustion. Also, it might sound counterintuitive at a concert, but stay away from alcoholic drinks. Alcohol dehydrates you, and if you're gonna spend hours under the blazing summer sun, that's the last thing you want.