Are you getting General Admission tickets, or specific grandstand seats? And are they just race day, or the weekend?
I went for the first time last year. My boyfriend and I had weekend GA tickets. For Friday practice we snuck into one of the grnadstands
Then once all that was done, we took a walk round the whole circuit to find a good spot. For Saturday and Sunday, we ended up on Club corner, which was a really good view. We could see them coming out of Stow, down into Vale and then round Club. And it happened to be where a lot of the action was!
One problem with GA tickets - if you want a good view, you need to get there early. We were there for when gates opened on the Sunday (and the Saturday, but that wasn't so busy), and by the time we'd walked to Club the crowd was building up. I thought I'd be bored, but we took books and magazines, and the early morning radio kept us entertained! I would say take some fold up chairs, some big brollies, waterproofs, sun cream ETC. If you're camping, it's a bit of a treck to walk back to the tent, so you're better off being prepared for any eventuality! Unfortunately, if you've only got General Admission tickets, I don't think there's anywhere covered to stand, so brollies will have to do!
As for other, specific grandstand seats, I can't help you out much! Where we snuck into on Friday, Luffield, was a pretty good view, and nice and covered! And it would mean that you don't have to get up at stoopid o'clock to make sure of a seat!