According to the professionals that produce the touch up spray paint, there are 2 things that will make a big difference in the use of aerosol spray paint.
1. Shake the can vigorously for a long time.
When you think you've shaken it enough, do it longer.
2. Apply 3 or 4 coats to the item you are painting. This will help greatly to reduce the amount of fading that can occur. It's not a bad idea to prep the item to paint by roughing up the surface and making sure it's clean and dry.