"You can burn as many calories doing 30 minutes of sprints and rests as you can in an hour going at a steady pace," says Jacque Ratliff, an exercise physiologist for the American Council on Exercise.
If you want to build core strength fast, grab those cannonballs with handles. "You'll get the most tricep activation if your elbows go straight back—not out—as you lower down," says Ratliff.
That's how long it takes to start seeing results.
For a serious side workout, trainer Gunnar Peterson suggests seated angled knee-ins. Lift your left knee up and bring it in toward the right side, then switch, bringing your right knee to your left side, almost like you're running in place.
"It makes them look perkier." If you're doing it yourself, add a second coat, from just above the crease of your butt to about three inches below.
Lunges are horrible, but if you're going to do them (and trainers all say that if you want a cute behind and taut thighs, you need to), get the most bang for your butt.
Consider a weeklong bloat-elimination plan, says Robynne Chutkan, a gastroenterologist in Chevy Chase, Maryland: Seven days before the beach, stop drinking alcohol; five days before, cut the gluten ("It causes water retention"); and two days before, lose the dairy.
Do three sets, starting with eight reps per side, and build up to 20.
Capsaicin, the chemical that makes chilis hot, also causes the body to burn more calories, according to research.
Keep these areas dry (and bump-free) by putting antiperspirant anywhere acne usually forms.
If someone is doing your spray tan, ask them to "spray a little tanner under the cheeks," says Anna Stankiewicz, a spray tanner at OC61 in New York City.