One of my favorite resources are City Directories. Through City Directories, you will find out important information such as physical address, occupation, who was living with them, etc. My favorite website for searching City Directories is Fold3.com. Because most, if not all, of my ancestors came from/through Philadelphia and/or Newark, NJ, this makes Fold3.com a great website for City Directories.
Most websites that house City Directories have a search function. The first step is to pick the State, City, and Year directory you want. In the following snapshot, I picked Newark, New Jersey for 1889. I will be looking to see who was living with my Gr Gr Gr Grandfather, Edward V. Eckert.
After searching for Eckert, it will find hits for that name found on any page in the Directory. In the following snapshot, you'll see that I found my ancestor Edward V. Eckert, living at 20 W Kinney, as a jeweler.