[]{}
I worked for a John Deere dealership in college. A couple of times I had to install decals. Many of these were MASSIVE, six feet+ long and up to a foot wide in spots. The soapy water is the trick, it allows you to move the decal all over the car. Once the soap and water dry, the sticker is set and your done. Don't rush, with the soapy water you'll have plenty of time to work.
One last thing: Give your selfplenty of time, no reason to rush. Give yourself plenty of work room, be sure you can move about freely. Do only one side of the car at a time. Work in the shade, on cool day, preferably inside. All of these things will slow you down, slow down the drying of the soap, and calm your nerves. Use a squeegy to push "gently, very gently" push out the air bubbles.
Go look at another car, few decals are "perfect" Thus you, are trying to do an excellent job, not a perfect one.
Finally, remember the golden rule, the enemy of "good" is "better." doh
Regards
Joe