Have a look at the
Gallery pictures on the site to get some ideas for angles and compositions. There may be possibilities to shoot inside the vehicle or to get some detail shots when it is not on the track.
Look at where the light is coming from and whether it's a sunny day or cloudy try to make sure you have the brightest part of the sky somewhere behind you. That will be much easier than shooting towards a bright sky. Look for vantage points where something interesting will be happening - a corner, a chicane. Think about long shots and closer shots. Your main creative tool for things which move is shutter speed. Use a fast shutter speed to freeze action and get crisp, sharp images. This is best for vehicles coming towards you (almost) head on. 1/500 is a good sort of minimum speed for such shots.
Also try some shots which emphasise speed by using a slow shutter speed and panning with the vehicle to create a blur in the background. A shutter speed around 1/125 would be a good starting point for this kind of shot, but it depends how fast the vehicles are going. The slower they are the slower the shutter speed will need to be. This takes lots of practice (for most of us). If you can practice beforehand it should help. If on the day you are struggling to get any keepers with this technique then I'd suggest you go for "safe" shots and increase the shutter speed to ensure you get shake and blur free images. If you have IS/OS etc then it might fight your attempts to pan and spoil the results. You may need to turn it off for panning.
Fencing is the next hurdle (probably the first actually). I have no idea what the track is like, but usually there will be safety fencing everywhere, which will make it very difficult to take shots which make the fencing vanish. The best solution, if you can't simply shoot over or around it is to get as close as you can to the fencing and shoot with a wide aperture (low f number). That will help to throw the fence out of focus. If you do have to shoot through fencing then consider how the light is falling onto it. If you can find a shady patch or create your own shade for the bit of fence you are shooting through then it will become less noticeable. If it is glinting in the sunshine they you might have a hard time to pretend it's not there. Try to find shade if you can.
Another issue you need to consider is focusing. How fast can your camera track a moving subject? Will it get confused by fencing? Can you pre-focus on a point and wait until the subject arrives in order to take the shot? I don't know. It's just something to ponder.
It's a good idea to have a look through the
motorsport photo sharing forum to get some ideas, but be advised that what works for some circuits, weather and lighting conditions, individual photographers and specific camera gear might not apply to all.
Sorry if that all sounds a bit OTT and complicated, but that's my top of the head thoughts on the subject. I'm not sure how to make it any simpler than that. It's simple when you know, but when you don't there is a lot to take in.
A couple of examples....
Long shot at 1/1600, shot through fencing....
Panning shot at 1/125....
The most important thing is to have fun. Enjoy the day. Do what you can, photographically, but don't beat yourself up if it proves difficult. Motorsports really benefits from practice. I don't get nearly enough. If this is your first time then you may struggle. All you really need is one nice shot to remember the day by. Anything beyond that is a bonus.
