Martinique is a wonderful stop!
1) Avoid just "going into town"..unlike many of caribbean islands, the town is actually a town. It isn't a series of tourist trap shops.
2) Hire a driver or rent a car...reserve early, there are only a few agencies there..take a drive! The scenery rivals California's- parts look like napa valley- gorgous
3) The beaches are amongst the best in the world. Clean, expansive, picturesque, with facilities nearby. Oh, and French, so tops optional.
4) There is a ferry that leaves the port area to a nice beach & restaurant area- many enjoy that.
We spent a full day there, including some time "in town"..no signs of crime- in contrast from what another writer thought, we've been told by ship personnel that the clearly the most dangerous port in the entire caribbean is St. Thomas. Rapes, robberies, even murders within a few miles of the ship- be very, very careful!! In St. Thomas, pass on looking for that $3 bottle of rum & simply stay on the ship and relax in comfort and safety...