If the surface you're applying the paint to is smooth then I'd say the paint is possibly going on too dry. When spraying solvent based paint with professional spray guns one can choose the speed of the solvent based on the temperature of the day you happen to be spraying. On a hot day you'd use a slow solvent. On a cold day, a fast one. Generally speaking with a gloss finish you want the paint to flow out on the surface it's being applied to. In other words you want all the paint droplets to land on the painted surface and flow together creating a smooth surface rather than sitting there as individual or groups of droplets. It's a sort of balancing act. Apply to wet and the paint runs. Apply to dry and it doesn't flow. With spray cans you have no control over the solvent that was used to thin the paint, but if you're having difficulty you might try spraying during a cooler part of the day to see if it helps.
