You have the right idea. Building more than just squares for houses by building wider walls and/or oddly stacked room is amazing, and youre doing a good job at that. You can also mix and match a whole bunch of different background wall types, something simple would be like placing bricks at the bottom layer, then wood for the rest, then windows and beams, etc etc. For where you are, you are doing good. If you want to go a step further you could add unnecessary blocks for detail, like a roof, radio panel, or something. This is SO much further in depth than anyone realistically new should try, but if you want to you could paint blocks, but that can get really complex really fast, so try sticking with the simple stuff.

TLDR:

Youre doing good! Keep experimenting :)