Lots of folks ask me how I create my models, so I'll take a minute to explain.
I use ordinary 2D graphics software to create my designs. No 3D programs are involved. I start by drawing out the lines for cutting and folding, and then I print out the un-textured version and assemble it to make sure that everything fits together as expected.
Once I've completed that paper test, I start adding the textures. Over the past couple of years I've built up a large collection of visual elements -- brick wall sections, wooden wall sections, windows, doors, lamps, and so on. Many of the visual elements I use are from photographs I've taken myself, and I also do quite a bit of designing from scratch if I don't have a good photograph to work from.
I choose different elements that look good to me, and I combine them piece by piece until I'm happy with the overall look and level of detail.
Then I blend these pieces together by adding shading and highlights. I also add lots of weathering for a lived-in look. You'll notice that there's bird droppings on the roofs and mossy growths on the walls, which are the kinds of details that I love to see on real buildings.
I make sure that all of the visible surfaces are textured, including the underhangs of the roofs, so you don't see any blank paper there. While I try to keep my models pretty simple in construction, I usually add a couple of little features such as a chimney, dormer windows or balcony to give them a bit more character and make them appear more complex, but without adding a lot of assembly time and fiddly bits. I want folks to be able to build my models quickly and without a lot of tiny parts, but still have them look great.
Finally, I use a book layout program to create the multi-layered PDFs, and then wrap up all the pages into a ZIP folder.
It can take me anywhere from a single day to a couple of weeks to finish a model. Typically, it takes me three of four days to complete a medium-sized structure. I aim to produce about one model per week, and I sometimes take breaks to gather up new ideas, create new visual elements and work on other projects that interest me.
I usually work on one model at a time, but I almost always know which model I'm going to design next before I've finished the one I'm working on.
So that's probably way more than anyone wants to know. But if you have any questions, I'm happy to answer them.