Here's something you'll love to learn: Your shoulders and upper back tend to carry less fat than the rest of your body, so the right exercises can give this area a nearly instant makeover, says Ramona Braganza, a celebrity trainer who has worked with stars such as Anne Hathaway and Jessica Alba. Braganza's workout, below, hits every major upper-body muscle and will help stabilize your shoulder joints, improve your posture, and build that strong, toned look you're after. Using five-to eight-pound weights, perform 15 to 20 reps of each exercise and go from one move to the next with little or no rest between. Do two or three sets three times a week. Hold it right there: Build strength with this muscle-isolating isometric workout . Four Top-Tier Moves 1. Reverse fly Grab a pair of dumbbells and stand with your feet hip-width apart and your knees bent. Bend forward at the hips and let your arms hang straight down from your shoulders, palms facing (a) . Raise...