Painting Tail lights.. Help

I'm very new to the modeling scene, i am working on my first car ATM, (Lancer-Evolution VI '99 New Zeland Rally Edition) and i was wondering how to paint tail/head lights. I checked the tamiya site but it was confusing on explaining which side of the light to paint with what colour.. Also, should i leave the space where i will put the head lights white? or does it not matter. (i mean the space on the body of the car, where the tail lights will be attached) And my last question is about sand papering. I just modelled on larger fogs (i'm not going to make this model like the one on the box) and i need to know what kinda of paper i should use to sand the putty (Tamiya Epoxy Putty) and not damage the plastic surface. Thnx for helping this newbie out.

Generally you should paint them from the inside for a realistic effect. You must paint the space on the body silver or something similar (as indicated by the instructions if I recall) to bring out color (I use bare metal foil, which is as close to real chrome as possible without actually metalizing it.) Pretty much any sandpaper that can sand off putty will also sand off plastic, you will just have to use caution on how much to sand off.

Paint the outside with clear red, and you'll be fine for the time being. As your skill progresses, you can apply chrome foil on the back to simulate the reflector part of the red area, or paint the inside or both sides to change the darkness of red.
The headlight bracket should be painted silver, or apply self adhesive chrome foil.
The rating of sand paper you usually use are something between 400 grit and 2000 grit. Personally, I think 400 grit will leave too much scratches, so use it only when a body has very big gap. If you work the way up to 1500 or 2000, it will smooth the surface, and primer should fill any scratches left on the body.

Lemme try to understand. Paint the inside of the light clear red, and on the body attach chrome foil? And for the grit paper, who makes them? or does it matter. Thnx for your help.