How should I texture a low-poly model? For example, I have modeled this car and now I don’t know how to texture it.
It has only 242 polygons. How should I texture doors and windows if it is one entire mesh and I don’t have drawing tablet to paint by hand? Should I make a high-poly version of this model with doors and windows separated, texture them and then apply the texture from the high-poly model to low-poly? What is the common approach to texture a low-poly model?
That isn’t a problem. You can assign materials for each face individually. Just create multiple materials in the material tab. Then go to edit mode and select the faces which should be of a specific material. Then click ‘assign’ in the material tab.