Actually wear the workout gear you pack but never use.

Getting in better shape is probably the most notable New Year’s resolution — and a cruise vacation can jump-start your regimen: that is, if you resolve to put on that workout gear and move. Set off around on the ship’s walking track, take a yoga class, or hit the elliptical in the fitness center. Many cruise lines also offer active shore excursions that involve hiking, biking, and paddling.