Writing in the King's County (New Brunswick) Record, Diana Lynn Tibert has an excellent article on how to solve some of those genealogy problems:
"Some individuals are mysterious. For whatever reason, they leave scant evidence they existed. At times, it might feel as if they didn't want to leave a footprint in history and wanted only to escape into anonymity. Or maybe they simply lived by meagre means.
"The trouble finding information on these mysterious individuals can leave a hole in an otherwise perfect genealogy. Call them brick walls or elusive family members, either way, the best method I have found to dig up data is to isolate the problem."
You can read the entire article at http://kingscorecord.canadaeast.com/friendsneighbours/article/749454.