Don't get in the way.
People are at festivals to have a good time. However much you may invest behind your big idea, this is about great music, not brands. If you try to put yourself between the audience and their favourite act, they won't thank you for it. Work with the event; don't try to dominate too much.
Remember where you are
A field, possibly in the middle of nowhere, is not the place to try out your latest all bells and whistles Bluetooth campaign, or launch a whizzy mobile app that requires the latest smartphone. Handsets will be dead by the end of the first day, and that's for the revellers who didn't just swap their sim card into an old Nokia 3330 for the weekend.
People are there to have a good time, not to learn about your brand
This isn't the place for a complicated message. There will be beer, more beer and then chasers on the side. If you're trying to get across an overly complicated campaign, it's unlikely anyone will remember it by the morning after. Keep it simple and direct.
The music is only part of the fun
Remember, they're living in a field for days on end. This isn't just about what's going on while the bands are playing. The best time to reach them could well during the down time in the campsites. There are all kinds of outdoor display opportunities at some festivals. Use them well and they could be effective. Even better, have something free to hand out that might actually come in handy to someone with trench foot and a hangover the size of the Pyramid stage. That's always a winner.
Be cool, or don't try
Don't try to be one of the lads. Don't try to join in if you fear your brand message sounds a bit like the equivalent of someone's wacky dad gatecrashing the party. If you can do cool, then do it well with as few words as possible, but if you can't, keep it classy. A festival audience can spot a dud a mile off, and will call you out on it too.