4. Jump to It
A jump rope burns more calories than a treadmill and works your entire body. Michael Olajide Jr., a former WBC Inter-continental Middleweight Champion and cofounder of Aerospace High Performance Center in New York, suggests hitting the rope twice a day for at least three minutes each time. Running stairs, hiking, and sprinting bring similarly speedy results, says L.A.-based Equinox trainer Michael Carson. "You should always be engaging your core and the large muscles of your hips, glutes, and thighs," he says. "These areas will maximize calorie burn."

5. Train Like Tom Brady
For a quick overhaul, it's best to work several major muscle groups at the same time, Carson says. Lunges, squats, and balance exercises are ideal, especially when you focus on form and duration rather than speed. If you have time to target only one body part, make it your shoulders. "They build very fast and can give you a tapered-waist effect, which makes you look better in a shirt or suit," Carson says. Just remember to rest for a day between workouts to give your muscles time to recover and build.

6. Go Easy with the Scissors
A haircut before your trip isn't just about looking clean-cut—it can make your face appear slimmer if you don't take too much off. Curly or straight, side-parted or spiked up, hair type and style matter less than making sure you don't whip out the clippers and give yourself Buddha cheeks with a buzz cut. "Don't get your hair cut too short," says Beverly Hills stylist Ryan Crupi. "Creating height on the crown of the head and length over the nape of the neck creates an egg-shape look that thins the face." But for guys who are losing their hair, leaving it longer will make it look more meager, so the choice is yours—you can look thinner, but you'll also look balder.