Love all of the techniques and tips listed here. Spot on across the board. The only thing that I would add is that we had the "standard 1-3 shots" but we would make sure that photo #4 was the "personality shot" of the car. Then, we'd continue on for about 30 more standard shots.
The personality shot was what we considered to be the most important shot of the car. It could be the vehicle from a strange view, for example a shot down through the sunroof into the cabin. Action shots are nice as well with features. For example, instead of just taking a picture of the rear view camera screen, put it to work. Have a guy pushing a baby carriage behind the car as you're taking the shot of the screen.
If the car was a normal, no frills, nothing-to-it type of vehicle, we would try to get it at a clever angle or with something interesting in the background. Imagine parking it close to the building with the dealership marquis in the background and taking a shot from the ground level looking up along the side.
Props work as well. An empty trunk means nothing regardless of how big it is. Throw a set of golf clubs in it. Cupholders? Put a huge drink in it that wouldn't fit in most cars. Recline the passenger seat all the way back and have someone sleeping comfortably in it.
Get their attention with the fourth shot. Consistency is key for all of the other shots, but believe it or not people will look at more of your inventory items if you put some creativity into the fourth shot. Clicks on that shot went through the roof and we would have people come in and mention the shot to their salesperson.
Sadly, I just checked the website of my old dealership and I see they stopped doing it. Unfortunate. I know the camera guy hated me but he was the dealer's grandson so I had a captive audience.