-
danciupuliga Gosh, not sure there was a single tool, but in lieu of an actual post: thegenealogist.co.uk is excellent for UK research, and I used findmypast (also uk though), then ancestry.com and myheritage.com combined—which would also lead me to familysearch.
-
danciupuliga Speaking to relatives is possibly the biggest tool, but I only had access to my parents (and respective grandparents were either deceased or it would be too difficult). Getting full copies of marriage certificates when in doubt was a big help to close "bugs" in my research.