Hmm, tips. I didn't camp last year so I can't give you many about those. I'd say: Take a plastic mat or something to sit on (by sat evening there are very few patches not covered in food), take suncream (of course). I'd also recommend moving around, but it depends what you like. If you're prepared not to get the absolutely best places, but to see people and get the atmosphere I'd say move around as much as possible.
The recent sun has reminded me of sitting last year, sipping cider and chilling as the sun set to Turin Brakes. Aah to be back there again.
Thats all off the top of my head. Have fun :)