Well sometimes I go on my own or sometimes I take my mate or I just might meet people while I am down there.
Normally the events are themed so Supercars, Italian exotica, Modified cars, etc. Essentially though you just look at the cars and eat some brekkie.
There are certain rules though. If you are on 'theme' you get to park on the start - finish straight. Slightly off goes in the pits and gravel car park and anything else vaguely interesting goes in the hard standing car park. After that it is the field along with the general public.
The main thing is that you go there and get what you want out of it. Essentially they are car enthusiasts like you and me so most of them are quite approachable and talkative.