Alright, so WB. This is only going to applicable to newer, higher-end-than-most-wal-mart-inventory cameras. There are very few cameras that have a real accurate auto WB. The "best" way to try and get the right WB would be to use a white card, but if you forget it or don't have one, then that wouldn't be an option. In this case, take a shot using auto WB. Check it out in the image review on the LCD screen, or monitor/PC if shooting tethered (which no one really is going to, short of professionals), to see if there is a color cast. If you don't like the color, look at the image info to see what the WB was set to by the auto system. Set your custom WB temp to a slightly cooler (lower K) if too warm, or to slightly warmer (higher K) if too cool. These K settings are opposite of what most people perceive, ala HID headlights where the higher the K, the bluer the light and vice versa. The next key step is to keep shooting and practicing WB adjustment. There is no magic camera that will take a perfect (subjective) picture right out of the box or in any auto mode for the most part. So what is critical is to learn the relationship between shutter speed, aperture, and ISO, because if these settings are askew to start, auto WB will likely be off. Anyone who has set up a professional shoot, whether it is of a car, model, product, etc, will tell you that one does not simply show up with the camera, take a shot and then done. There is most definitely a period of time allocated to achieving the desired camera setting, so don't be afraid to park the car, take a shot or 2, then sit there on the ground for 5 minutes until you get the settings your looking for. Time and experience will improve your ability to correctly judge WB settings, and trust me, it won't take as long as you think.
Or...
Shoot in RAW and adjust later
