Originally Posted by Mr. B

Start with a clean and waxed car surface. Best to do this on a day that's not at all windy. Figure out where you want the decal.

You'll need a spray bottle and in the bottle put a wee bit of dishwasher liquid and water. Spray the area you intend to cover with the decal, so the car surface is now wet with this solution. Peel off the paper on the back of the decal and spray the sticky surface of the decal. Now apply the wet decal to the wet car surface. You'll find that you can easily move the decal around to position it exactly where you want it. Apply a flat surfaced piece of plastic to the decal to get out any air bubbles. They make pieces just for this purpose. This wet application method makes it easy to get the decal where you want it and easy to remove the air bubbles. If, somehow, you mess up, just pull the wet decal off & start over. Once the decal is in place and with no bubbles, allow it to dry for several hours. Then, you're good to go. Here's a photo of my racecar with LOTS of decals:
http://www.motorsportsimaging.com/SC...01_04_0067.htm
Mr. B