Good advice from the community so far. It's my local circuit so if I can offer some more specific Silverstone info.
1. Go to other events prior to f1 (As AndrewC says) - learn where the best shooting spots are prior to rocking up. The WEC in April is a great choice
2. Friday is the best day for photos due to crowd numbers - if you try and find your way around then you will be in danger of wasting an opportunity. You need to know where you are going to shoot from and how long it takes you to move about before you go to the f1 meet. Saturday is ok but exponentially busier than Friday, Sunday is rammed, like you will only be able to shoot from your seat and depending where on the straight you are, you are unlikely to get shots you will be happy with due to fences and walls.
3.Fences will get in the way - its a fact - you need to know where you can see over them and/or through them prior to going. you will not be able to get close to the fence on sat or sun unless you German your spot from 6am or when ever the gates open.
4.learn to Pan..... low ISOs, slow shutter speeds (1/250 max) and track fast moving vehicles. Or you will end up with nasty stationary cars
I posted in another thread about locations and 300mm reach at Silverstone.
"I don't agree that 300mm is not enough for Silverstone, it has been pretty successful for me, sure a TC will help but ultimately its depends on what kind of shot you want...a close up of the drivers eyes as they turn into Stowe isn't going to happen, but if you are realistic you can get pretty good shots as long as you choose your location well.
I've posted links to large images on a few so you can actually see what is possible - i'm using a 40D for these so only 10mpx so most bodies now should capture some extra detail compared to these as well - all from spectator areas-never been media. all with sigma 100-300f4 non dg (No stabiliser)
40D @ 300mm - no TC @ Luffield complex grandstand - so behind a raft of spectator terracing as well
British GP 2009 by
Fireproof_Art, on Flickr
40D @ 300mm + 1.4x converter @ at exit of brooklands pressed up against the fence
(the full size image is 3 times bigger than this and quality is great)
8 by
Fireproof_Art, on Flickr
40D @ 300mm no tc from inside of stowe - vale. behind fence again but not always accessible for big events.
Brundle WEC 2012 by
Fireproof_Art, on Flickr
40D @300mm no TC from the loop (between village and wellington straight) shooting through vacant photographer hole - again not always accessible.
BritCar 24hrs Silverstone #88 by
Fireproof_Art, on Flickr
40D @ 300mm (NO TC!) from club gold grandstand - granted this is a pretty large crop as I had whole car in frame, only a 10 megapixel sensor though
Sebastian Vettle by
Fireproof_Art, on Flickr
And another one from Club - 40D 300mm no tc - i'm in the middle of the grandstand as well.
Jaime Alguersuari... 2011 Silverstone by
Fireproof_Art, on Flickr
Hopefully this will give beginners a better idea of what is possible and a better insight into whether they need to have gear envy or not. I'm not saying my photos are artistically/compositionally wonderful - this is how close you can get for under £700