Here’s some helpful tips from Ancestry.com:
“You’ve just discovered great-grandma’s maiden name, but following that initial rush, you get this sinking feeling when you realize that researching John Smith isn’t going to be easy. But don’t cast hope aside. Your John Smith was an individual and while challenging, researching ancestors with a common surname is absolutely doable. Here are some tips:
1.) Create a Profile
Gather up every snippet of information you have on that person, from either their own records or the records of their children. For example, beginning in 1880, federal censuses asked the nativity of both parents. If you don’t have a birth year, you could estimate based on the birth of the eldest child. Even getting within a 20 year range can help narrow your results greatly. Milk every drop of information from every record you have for the family and form a profile of that person. Every piece of information will be helpful in identifying your relative.
2.) Collect Addresses
Addresses are wonderful identifiers and they can be found in censuses beginning in 1880, some vital records, obituaries, city directories, and home sources (think letters, postcards, photographs, even the inside covers of books) among other sources. Assemble them chronologically to zero in on your ancestor’s location at a particular time.
3.) Conduct Whole Family Research and Beyond
Learn as much as you can about the family structure. While there might be a kazillion John Smiths, there won’t be as many with wife Margaret, daughters Susie and Jane, and sons William and Henry. And if you’ve got ages, you have a very good chance at being able to identify them in the census. In censuses where a relationship is stated, you can use family members to narrow your search on Ancestry.com.
You’ll want to go beyond that though, making note of every sponsor, witness, business associate, neighbor—anyone you have record of interacting with the family. Perhaps your John Sullivan traveled to America with Peter Walsh who also appeared as a witness to his child’s baptism. Or maybe it was his sister’s husband who was a witness at his marriage. Getting to know the people who associated with your ancestor will also help you identify them.
4.) Collect Autographs
If you have a record that your ancestor signed, use that signature to compare with signatures in other records he or she signed. Seeing your ancestor’s “John Hancock” is a thrill in itself, but it can also be an identifier if it’s distinctive.
5.) Use Records in Tandem
The timelines we talked about in the Maximizing Success” article are a great way to make records work together. Use city directories and other records created around census years to find your ancestor’s address during that year. If they lived in a large city, this can be very helpful in narrowing your search to a particular ward or enumeration district. For census years 1880-1930, you can search for the street name or for other main thoroughfares (which often served as the boundaries for wards or enumeration districts) in Steve Morse’s enumeration district finder. Once you pin down the district where your ancestor lived, you’ll be able to narrow your focus to people with that name in that district.
Census records from 1900-1930 include immigration dates for immigrants. Some death records and some state censuses include “how many years in the U.S.” Use these dates to narrow your search in immigration records.
The bottom line is to pick every shred of information from each and every record you find and use it to form a more complete profile of your ancestor. The more you know about him or her, the better your chances of success for finding your Smith (or Kelly, or Sullivan, or Jones, or Johnson, or Miller…).”