follow the the tech sheet as closely as possible. Waiting time between coats of any paint is the secret. Don't be in a hurry. Don't color sand the basecoat unless you want streaks and unless you wait a day between clearcoats you should not sand the clear. If you've messed up, your option is to let the clear dry, sand and recoat with clear after it has dried. Don't sand into the basecoat unless you want to start over from the start.
This comes from years and years of painting from enamels to b/c.