I used to be into my car photography.....
As already said, if at a show then get in close with a wide angle.
Don't be put off by crap weather, the shots are still there for the taking.
Although not possible at most shows, owners are usually happy to reposition their cars if they think you stand a chance of getting a half decent piccy of it; it's worth asking!
Byker28i - nice to see some Tiv piccis on TP

Here's some I took earlier.....
1) The awesome TVR Speed 12, pre-restoration. I love the OTT shapes in this image.
2) TVR Vixen
3) TVR T350
4) Can't remember which model, but no prizes for guessing the make
5) TVR Tuscan, Griff 500 and a 450 SEAC in the Lakes
6) TVR Griffith 500 in a wet and cold Lake District