A lot of good advice here. I'll add a few tips.
Scout the location early.
Finding places where you can stand with a camera, with no obstructions, that has the right angle on the track can be hard. But it'll be harder if all the spwctators are there first. When you scout, think about how the cars will come through the area. Except for the slow-shutter panning shots mentioned above, straights are boring. Corners give you all kinds of angle possibilities.
Scout with a lens you think you'll use. The distances can be greater than you think. (Don't hesitate to rent a lens from Lensrentals.com if you don't think you have the right one. But get it a day or two early, so you can test it and get to know it a bit before the race.)
Red Biull Chasing, Montreal GP Nikon D3s; Nikkor 300mm f2.8 MF
Look at what will be behind the cars. Pit crews and spectators can make a shot a lot more interesting. Pine trees, less so.
Renault Re-enters, Montreal GP Nikon D3s; Nikkor 300mm f2.8 MF
Practice focussing. Practice with the autofocus modes of the camera with the lens you'll use to see if they are up to the challenge. And practice manual focussing as well. See if it's better.
Shoot high-speed bursts. Cars will pass through focus with varying, but often good results (if you've practiced). Know your camera's buffer so you don't over-shoot it.
Anticipate. There is delay in all camera systems. Get used to it and compensate for it. You have to press the shutter before the moment you want happens. This is more true of racing than most things. It just moves faster. (more reason to shoot short bursts)
Watch your exposure carefully fo the first few passes at any location. Cars are shiny. They often are much brighter than anything about the location has lead you to believe. It's easy to come away with a lot of hard-clipped highlights. But don't under-expose either. Dust can eat up the light sometimes.
And most important... don't forget your earplugs. Racing engines hurt my ears!