Most importantly, as Joanne has already mentioned - wear comfortable shoes!
Try to plan where you want to go, plan a route - you'll need it.
Last year there was a kind of VIP area for snacks and drinks etc - get in there if you can cos seats in the other 'dining' areas are few and far between and trust me, after 5 hours you'll need to rest your feet and it's amazing how mean people can get when there's only one free seat left!
Everybody whinges about people who take them, but...... take a small trolley - your fingers will be cut to ribbons.
Take plenty of water with you.
You'll need loadsa money!
And if you're driving and park in the underground car park, take great care to note whereabouts you park. My friend and I were left wandering around the labrynths for about an hour looking for her car - we knew we were on the correct level, just couldn't find the car!
Go on the Sunday if you can and try to arrive about 9am if you're driving, closer to 10am if you're not - you'll just get left to wait outside till they're due to open.
They have a cloakroom - use it!
And take one of those little 'handy fans' with you for when you're close to fainting due to the heat and the crowds!
But most of all - have fun!
I'm really envious - I won't be there this year. :cry: