The base color is always sprayed with an airbrush to avoid ungraceful handbrush marks.
The color is of course different from a model to another one but for Star Wars vehicles, it is very often the same : a very clear grey made from 7 volumes of flat white Tamiya XF2) mixed with 1 volume of skygrey (XF19)
To perform the paintjob, I apply many successives thins coats until I get an homogeneous tint.