A simple oil based wash takes it to another level. There are many pre made but I like to make my own, this way I can make it as heavy or light as I want.
Heres a simple technique, all you need is Turpenoid and an oil paint. I like to use Abteilung black or umber, they get into recessed areas and show them off better than lighter colors.
1. Pour some Turpenoid into a small cup or container.
2. With a tube of a decent oil base paint, take a smal amount at first and mix it into the Turpenoid. Adjust it accorningly as you like. About the only thing you could do wrong is make it to strong, in the area of 80/20, 90/10 or so.
3. You can either pin wash this mixture on specific parts or do the entire vehicle.
You can repeat step 3 if you want but know that a second or even a third wash will really darken it. 95% of the time one time is enough. If you get some wash in an area you want removed, simply get a clean brush and use straight Turpenoid on it until youre satisfied.
This is very simple and a fun step and decals actually go on easier after this step.
Any questions please ask. Try it on a scrap part first and "Just Do It" its easy and have fun.
Terry