As a genealogist, a question I find myself fielding often is "What can you do?" This isn't an accusation; rather, it's curiosity into what genealogists are actually capable of doing. I explain that I help people build their family trees, make sense of their DNA testing results, and find family records.
To give an example of my process, I recently decided to look into records from my maternal grandfather's family. From a small shtetl (village) in Lithuania, my maternal grandfather's parents immigrated to the United States at the turn of the 20th century. Using names provided by conversations with my family, I have used various databases to locate several lost relatives and build a fairly comprehensive tree.
However, the databases are incomplete, and I had not been able to locate vital records for my great-grandfather's birth nor his brother's. Until now.
Using records provided by familysearch.org, I combed the metrical books looking for my family. Using census and revision list information I had collection, I guessed the year of birth of my great-grandfather's brother. Lo and behold, I believe I found it!
When I say "I believe," there's one piece of evidence working against me: the last name is different! Something you quickly learn from doing this work, however, is that records can be wrong. Human error is a real thing. Based on the year, the name of the child, parents, and paternal grandfather, and town, I feel strongly this is my great-grandfather's brother. Ashkenazi Jewish last names were also fluid, so this could also be the case, although I think this is less likely. More likely, looking at the page before, someone was born with the last name written on my great-grandfather's brother's record. Perhaps the person who wrote it was looking at the previous page and copied the wrong last name. Even so, besides the other corroborating evidence I've collected over time, I will continue to look for more because that's what genealogists do.
And now, I help others do the same. Not only do I locate the record (and in this case, and unrecorded one), I analyze it against other evidence and give you my professional opinion on what it means for your family tree and history.