I know that I have written about city directories before. It bears repeating. If the directories you're looking for are not on Ancestry.com, or if you don't have a subscription, visit the library of the city where your ancestors lived. Along with the address where they lived, you might find their ages or occupation. Look for people with the same surname, especially within a few pages in the directory. Perhaps they were family. If you can, go to the address and take a photo.