While you can go pretty far using the Unity shading language, we will focus on the use of image-based texture maps mostly in architectural visualization. We illustrate this with textures from the Arroway website (http://www.arroway-textures.com/catalog), which are provided commercially in high resolution or can be freely downloaded in low resolution, under a Creative-Commons license (CC-BY, so attribution is required if you apply them in your projects).
Go to the Arroway website and browse to a texture that you like. We opt for bricks 002, which gives a nice weathered brick pattern. You get a preview of how the texture looks when applied to an example.
Note the hints that are provided here: real world size is 6m x 3.4m and the texture is seamless only in the horizontal direction, so you should not repeat it in the upper direction. Download the RAR archive and unpack it. It contains three files:
bricks-002_b030.jpgis bump map, hinted at 30% intensity,bricks...
