Those of you enrolled in Transportation Design programs will shortly be making clay models, if you're not already. Eventually you'll paint them and present them at crit. And no matter how different your designs are, every paint job in the room will have one thing in common: They'll all glisten with that plasticky new-ness, as car models are always painted to look like they just came off of the assembly line.
Might it not be interesting, particularly if you're designing an off-road vehicle, to paint your model to look weathered? Those painting techniques aren't likely to be taught to you by any professor, but there is a wealth of demos online by scale-model-painting hobbyists. Here's a quick video of a guy touching up reveals with a pencil and brush:
This slightly more involved video shows the demonstrator weathering a tank:
Here's a longer video of a guy darkening reveals and adding streaking and fading:
And here's a clever trick for adding simulated mud spatters by using a toothbrush:
These techniques give the vehicles a lived-in, used quality that makes them convincing replicas of the real deal. While they might not be appropriate for those of you designing the next Bugatti, if utilized on a model of a 4x4 or a post-apocalyptic survival vehicle, I think they'd go a long way towards helping to suspend disbelief. And isn't that the key job of a model?