There are a few articles in past issues of FSM dealing with this. I use cans for my cars and airliners. I use an automotive brand here in the UK that has a very wide selection of colours as well as various primers. Getting a very glossy paint job is tricky, I find. Either you spray a lot of paint and get a beautiful shine straight away, but risk having runs all over, or you do it the 'subtle' way, spraying several thin coats, varnishing, and polishing...
To ease the flow, you can warm up your can in warm water prior spraying. Spray in a well aired area (I spray outside). My shine is obtained with the 'subtle' method mentionned above. After a few light coats of paint, I spray a gloss acrylic varnish (of the same automotive brand, as it happens), or airbrush a few light coats of Furure, then let dry. Then I polish my paint with turtle wax until I get the shine I want. It's not an easy way to do things, and it takes time (hours sometimes) to get whay you want. Beware of sharp edges on your model: do not polish there too much or you'll go straigth to the plastic and have to start all over again! Use a soft cloth, white preferably so that you can see straight away if you've gone through the gloss varnish. If so, time to respray a little bit more...!