Autox photog tips:
(I think you're doing some of this already, these are just general tips)

Capture action. If there is no action (body roll, front wheels turned, cones flying, tires smoking, SOMETHING), then you might as well be taking photos of a car show.

Focus, zoom and frame. Blurry photos suck, and you need to be zoomed in enough to see the car clearly. But, you usually still need to capture some background... rows of cones, apex cones with pointers, something to give those who know what they're looking at some visual reference as to what's going on in the shot. (eye candy for those who don't know what they're looking at)

You can catch action in people's faces, too. Watch for newb drivers and especially newb ride-alongs, sometimes their expressions are priceless. And a lot of drivers get "race face" (akin to "rock & roll face" that guitarists get, but not as bad as "bitter beer face"), it can make for some good photos, too.

To get the really good shots, you have to take a lot of crap. I never have had the patience to do this... but, snap, snap, snap. Most of what you get will be crap... though I've seen really good photographers who's "crap" is still better than the average person's "good" photos just because it's clearly focused and well-framed.

Obviously, these are non-technical tips. I'm not a photographer, just a guy who's been around autox for a while and seen a lot of good and bad photography.