Firstly, what is a Maquette? - It is a small scale model done and used by artists to visualize the final piece, in early cinema it was also used to depict places imaginary to the directors, and used to the final film just before CG was available.
An example of maquette used in film, can be seen in the 1990 Tim Burton's Edward Scissorhands, this gave the chance to create dynamic shots at low costs. However, not using much of a maquette for environment, unless to do the futuristc model metropolis, same techniques were used to create props which later would be used in films.
Stepping onto the tecnhiques used to paint this same maquettes, many are used:
These 2 videos show some techniques being used in to paint models, either using a tiny brush to detail the model.
Understanding these techniques we will be able use similar and paint textures on the miniature models, also tweak it to offer it a more hand-made look.