Clear coat is always a toughie and is as much an art as anything else.
It sounds like your holding the can too far away and it's drying before it hits the surface. Clear coats need to be put on in a wet coat. Meaning that it looks wet when it hits the surface. BUT not so wet that it starts to run and drip.
Start spraying before you get to the object. Movle slowly and evenly about 6-8" from the surface. Practice on a piece of scrap to see how close and slow you can spray without getting a case of the runs :o