So far, I've picked Dakota, St. Louis, Brittany, Boston, and Duluth, Minnesota for my novels' settings. I know firsthand the terrain of rural South Dakota and the layout of Duluth/Superior.
I've been to Paris, but not Brittany, so I read travel guides and early 1900's accounts of leisurely wanderings through that northeastern department of France. It was important to my story to have that specific setting.
I've not been to St. Louis, but I found in my local library great drawing of its Mississippi River steamboat docks for a different historical romance.
I've probably not visited Boston enough to do justice to that well-known setting. I did attend a girls private school, so I can write with authority about that environment.
Maybe I can color up little old Park Rapids to be more exciting. It's hard to have summer sex by the lake with so many mosquitoes, though.