I mostly like to design and build houses and community lots myself. I can build from scratch without using any references. I enjoy making my own designs, but sometimes I like to get ispiration for the exteriors and for the build-style (Craftsman, Victorian, Contemporary, Modern etc.) so I google pictures of houses and buildings.
I do also like to download some houses and community lots from the Gallery and then edit them for using in my game (after editing them, I save them to my own Library). I like to download both furnished and unfurnished, depending on how I feel and what purpose the house or community lot will be in my game. I very often redecorate them as I love decorating, and also so that they will be more suitable for my sims in my game.
I also like to download shell-challenge -builds (going to do some more shell-challenge -builds later on, they are fun).
I also like to renovate, rebuild and redecorate some of the existing houses and community lots that are in the game and make my own versions of them.