4. Charge your cell phone. Nothing sucks more than needing help and not being able to call for it. Make sure your phone is fully charged and in good working order before heading out to the festival, in case there's some kind of emergency like a tornado, a fire, or if a band plays a cover song and you can't quite remember who originally did it and it's driving you crazy.
5. Find shelter, but not the wrong kind of shelter. If bad weather is coming your way but it's going to blow over relatively quickly, find some shelter and wait it out. Every Houstonian knows how much it sucks to be on the road during a storm, when many of the city's roads turn into raging rivers and later blissful, car-strewn lagoons.
Not just any shelter will do, however. Hopefully everybody knows not to hang out under a tree in a lightning storm, but not everyone knows not to get inside a tent during a windstorm. Don't head to that VIP tent when the wind picks up, or else they'll find your body days later crushed beneath what was a whirling dervish of complementary ginger beer cans and promotional lanyards.
Find something with real concrete walls and an actual roof to huddle in, if you can. If you can't find anywhere like that, find a low point like a ditch or a pit. Try to handcuff yourself to a water pipe with Helen Hunt if you can; this guarantees survival in any scenario. Unfortunately, the dialogue will be terrible.
6. Wear good, comfortable, protective shoes. At any outdoor concert, especially festivals, you can rest assured that, at the very least, the ground around the stage will be quickly churned into swampy goo by the stamping feet of the festivalgoers. Even if there's no moisture in the air or on the ground, it will turn into muck, simply because some filthy bastards would rather stand in one place all day and pee down their legs than go to the port-a-potties and risk losing their choice spot. Disgusting, but true.
Plus, if the wind picks up and debris starts blowing around, you don't want the only thing between your foot and a ballistic chunk of paneling to be a thin string of flip-flop rubber. Wear shoes that cover your entire foot, preferably with socks. Full-on steel-toed boots probably won't be necessary, but couldn't hurt, and can be bought on the cheap from any second-hand store.
Basically, if you're going to an outdoor concert, dress your feet as if whatever's covering them may either save them or get ruined forever.
7. Don't be a douchebag. Honestly, the secret to avoiding trouble at an outdoor concert, or any other public place, is often simply to not act like a raging dickbucket. This means do not start a mosh pit when it's inappropriate, and learn how to mosh. It's an actual dance, you know, you're not just walking around shoving people.
Don't get so drunk you become loud, aggressive, or otherwise obnoxious. Don't talk to your stupid friends so loudly that it interferes with other peoples' enjoyment of the music. By simply not being a jerk, you could avoid sticky situations altogether, and if something bad does happen, who do you think a good Samaritan will dig out of the rubble first: someone who was nice, fun, and helpful, or someone who screamed "FREEBIRD!" at every band and pounded 24-oz. Bud Lights until he puked all over his shoes?
Yeah... enjoy the view from under those pylons, broseph, and best of luck to ya.