Get there early so you reserve your spot which means dealing with parking traffic too, depending on where you got your parking. Essentially lawn is first come first serve spots, and people claim space with blankets like 4th of July. Most people are usually are respectful of that and hopefully you don't have a bad experience where a person moves it. After that you can go get merch or food.

The last thing you want is a bad spot next to lights or over the hill where you can't see. Oh also expect people to be smoking weed back there. Happens more often than not.