Before you begin this project you need to have the following handy:
800 grit sandpaper, a bowl of water, paper, tinting product of your preference, paint, paint thinner, and tack cloths.
To assure the tint takes to the lens start by sanding the entire surface with 600-800 grit sandpaper. Pay close attention to the bridges and any corners. This will give the lens a soft scratched look. Wipe the edges with paint thinner and start masking off the area you do not want to tint.
Green painters tape works best for this. With the edges masked off, now tape paper over the backs of the lenses to keep over spray from entering the inside of the lamps. Check the masking one more time and if everything looks ok, start cleaning the prepped surfaces. The best way to do this is wipe them with a cloth soaked in thiner and come back with a second cloth to remove any dust.
With a clean surface you can now start the tinting process. The key in this step is to keep the spray and thickness as even as you can. Too much VHT or tint and the lens will look overly black. Too little and you risk the lens looking splattered. To give you an idea of the technique you wan to use I have prepared a video at: http://volvospeed.com/Mods/tinting_vht_niteshade_imron.html . A lot of painting comes down to practice but seeing it does is easier to follow than reading about it. With a little patience you should not have any problems achieving God results.
Apply as many coats as needed to get the results you want with the methods shown above. After you have the look you want, the key to a great result is clear coating. For that OEM shine take your newly finished lenses to a local paint and body shop. For a few dollars they will spray your lenses with a polyurethane clear coat. This coat will resist UV fading an cracking as well as help prevent any scratches from forming. All said and done this is a great modification to update the look of you car for under 50 dollars.