For festivals you often think it's a great idea to bring everything including the kitchen sink, but it actually works well if you pack lighter and preferably a bag on your back. Never take things to festivals which you care about as it's possible they met get stolen if not could possibly get wet or COVERED in mud. Oops. Take minimal clothing and only the essentials.
Plan your travel:
Getting to a festival can be a pain, if you live nowhere near you are lugging a hella load of stuff across the country. You can get trains and often busses from cities to festivals from certain places which is always handy. As well as this SMC Coach Hire are a company with coaches and mini busses available for hire, so if you are heading there in a big group or know a fair few people who want to chip in and split the costs together it can be awesome way to get there, easily.
With festivals if you lose someone/something it is pretty much impossible to locate again so make yourselves stand out. Get a BRIGHT tent (Go Outdoors have a great guide for finding the best one for your festival needs.) and find someone all of the people you are with can wear. Whether that be bright hair, carrying inflatables, wear fancy dress or something else fun, make yourselves stand out.