Read the can, because it varies depending on application. With a paint gun you generally give paint 5-10 minutes between coats, and then once last coat is applied you give it 30 minutes to flash before the first coat of clear.
The trick is light even coats. You don't want to get full coverage in the first coat because it will take forever to dry and its probably going to run.
If you want good tips check out Paint Society on YouTube. I watched a few of his videos before I painted my car. He has a few videos showing how to get "good" results from a spray can too.