I understand your question babyruth. That is the challenge. There are several ways to do this. I generally lay them all on the design wall and just look at them and try to imagine how they would look. Sometimes this takes a couple of days depending on what I am doing. Then once you come up with an idea of how you would like them to work, then start laying your pieces to coincide . Sometimes a 6" will work with a 3" to make a 9" which can stand next to another 9" then have a pice of fabric over them to make them the 12" to fit next to another. I am not sure how you want your neighborhood, but lets say you are doing rows, then you may have a 3" row, 6" row, 9" row and 12" row with the 12" at the bottom and this will give the perspective of you standing on a street and the others, because the size is smaller will give dimension as in a background. You get the idea?