lol, nah Dan's fine
Ummm....well. I guess from experience mostly. I know that sounds really clichéd, but that's the best way to learn in photography.
This is no disrespect to anyone on here, but some of my early 'shoots' looked similar to that of photos on here. But that's great for those people who go out there and do that, because next time you go out, you'll learn something that will improve your photos.
I did pick up a few tips from other forums, DeiselStation used to have a great photography section (it's still good) but it used to have the likes of Easton Change, Andy Wee, Scott Dukes etc on there. This was good for tips, but it was mostly on the subjective stuff, like composition.
I look back on some of my first 'automotive work', and it's shocking lol! Partly because I didn't have the same gear as I do now, but I made lots of silly mistakes, and fell into the amateur photography traps, like HDR.
Speaking of equipment, that's one main thing, and I don't really mean the camera. Any decent SLR will take awesome pics if you know how to use it, but if you want to do automotive work, then external lighting is a MUST. Even if it's as simple as a basic torch. That's what I used for the first time on that M3 car park shoot. I'm pretty happy with the way it came out for a first time, but I realise some mistakes I made, and next time I go out I'll try and improve on that.
I've been doing photography seriously for about 6 years, and experience is the only thing that will make you better. I still look back on photos I took when I started, they weren't brilliant by any means, but I wouldn't have made any progress without going out and taking those photos.
Going out with people who know what they're talking about is another really useful thing. When I met up with Steve (planetx), I learnt a few things that I never knew before, which was great.
Don't forget photography is a very personal thing too, so going out there and realising your 'mistakes' will help you progress and develop your style as a photographer too.