Where do you live? What's the weather like there? Reason I ask is that ideally, you want to spray paint out doors when the weather is around 70 degrees or so. Outdoors for air circulation, temperature for better paint flow.
Also, when spraying, start "off" the subject, spray in a smooth motion all the way past it and finish "off" the subject. You don't want to start or stop the spray "on" the object you're painting. And as mentioned earlier, multiple light coats are better than one thick one. Build it up, go over it a few times from different angles and positions.