ehow.com offers great tips and tricks on anything and everything, including a great post the proper technique for spray painting metallic fixtures and get great results! How to Repaint Metal Fixtures in a Bathroom is a step by step guide on what you need and how to prep and paint metal fixtures. Another great blog, Saving 4 Six, shows step by step photos of the three main steps of the process.
Step One: Strip down the fixture. Clean it up and scrape, sand, and strip any grit an grime to get the faucet cleaned and smooth. The smooth surface is necessary to help make the finished project look it's absolute best.
Step Two: Prime the surface! This helps the paint better adhere and will help to make sure the finished project holds up in the long run. Make sure that when you are putting the primer on, it goes on evenly in order to guard against pooling and running.
Step Three: Paint! After the surface has been primed it's time to paint the fixture! Pick a metallic paint that you like, and the fixture looks brand new, at a fraction of the cost it would take to replace the fixture. Repeat steps one through three on any other fixtures and you've given your bathroom a new look!