As you may be aware, I occasionally tinker with 3D graphics design as a hobby. I've never attended any courses for this, and I've never really had more than a glance at the help file, so I just learn new bits by clicking buttons and seeing what happens. Now and then I get lucky.
I have discovered texturing! This allows me to cover a surface with a picture. For example, supposing I drew a lighthouse/windmill/observatory on a tiny island in the middle of the ocean (hypothetically, of course). If I coloured it with flat colours, it would look something like this:
This creates a somewhat flat and boring look. And there's no background. I could try to sculpt a background, with trees, islands, cities, etc., but that would take forever to do, and three forevers to render. Instead, in order to make it all look marvelous, I essentially wallpaper it with pictures:
Thus creating the illusion of texture. The stone looks stony, the sails look saily, and the copper dome comes out a lovely copper colour. And there's a background! It's actually a flat panel with the picture, like the backdrop at a play, but it fits quite nicely.
It's not perfect just yet, but I'm still exploring. I'm excited, though, because everything I draw now can look more real.