We have all probably sat in an airport or busy area watching the crowd and imagining who they were...developing possible life stories about them. I started approaching my other works with that mind set.
Find either a vintage pattern or photo for a subject. Now the fun begins...develop a story. Who are they? Now it is all about finding vintage ephemera that helps everyone see their character. Sometimes I reverse the process. For example, I realized I had several Chicago and New York images. I decided that my "Chicago Gal" was a young, independent woman who moved to the big city to work in publishing during the late 40's. Now NY was a little easier when I found my "That Girl" in her modern 60's outfit. I used maps as my initial layer then built up finally find quotes that fit.
Call me crazy but I think it helps make the work more cohesive.