Hey, heres a tuty on making doors for your car, hope it helps ;)
For the purpose of this tutorial, ill be using my custom Nsx.
Firstly, we need to work on 1 view of your car at a time, so clear some room like so…

Now, we need to start drawing the outline of the door, don’t go too far out, or you’ll screw the perspective.

Now start painting the panel, try and match it to the rest of your car, and shade accordingly. Don’t forget that your looking at it from behind, so the mirror will have a glassy effect. Check mine if your not sure. Also you can do it to more of a classical brown colour, just select a dark brown – a good one is R:77 G:29 B:29 for your dark, then R:94 G:49 B:49 for your lighter shade.

At this point, you’ll probably think that the door is facing the opposite way, this is just a trick of your eye because we havn’t yet painted on the doors features. The next part of course is to do the window, just get the same colours as your stock tint (unless you’ve got a window tint job, simply do the same with the specific shades) A trick is if you want to get it see through, like reality, then just create your window on a different layer, then adjust the opacity to the level you like, check my Skyline for the result it gives!

Now here comes the trickiest part, the door panel. It really depends on what colour you want it, but I believe the best is a brown leather look. Of course now if you wanted to, you could add Subs, or whatever, it’s all up to you.

Now that’s the rear view done, time for the front.
You basically follow all the basics above, but without the interior paneling. So for this purpose, I’ll start with my door already painted.

So now we’ve just got to tint the windows, don’t forget your side mirrors should be next to the wing (edge) of the bonnet.
Tint the windows like the rest of your car. And that’s it. Front View Completed!

For side views, I still haven’t found a way to do them yet, but if I do I’ll upgrade the Tuty’.
Thx for usin, Lucas ;)
Edit: Just noticed i have the mirror in the wrong spec for the rear view, dnt worry, just move it along to the bottom right. ill get pics up in a week or so :)