Eat nutritious foods. Don't consume more calories than you need, and make sure the nutritional content of your food is high. The idea is to provide your body with all the building blocks it needs to build more muscle tissue, which means greater muscle tone, and to also encourage your body to shed fat, so that your toned muscles will show. Make sure you get enough protein, plenty of vegetables and fruits, and whole grains for energy.
Lift weights. The greatest and fastest increase in muscle mass comes from strength-training your large muscle groups: legs, arms and core (torso). If you have a gym membership, seek out the trainers who work there. Explain your goals, and ask for help planning a program that will give you maximum results but also help you avoid injury. Many trainers will have you work different muscle groups on alternate days, making certain you don't work the same muscle group two days in a row. During your first week, allow one full rest day.
Use home workout equipment if you cannot go to a gym. Dumbbells, an elastic band, a balance ball and a medicine ball are sufficient for most people to do adequate muscle-toning exercises at home. These are not expensive and are available at most sporting good stores. Basic curls and push-ups will tone your arms. Squats and calf raises are excellent for toning your legs. Instructions on how to perform various exercises are readily available online.
Work your core, even if you don't feel like it. Legs and arms are more fun to work because they tone up quickly. But while your eyes may not see dramatically toned-up abs in just one week, you'll be able to feel that your core muscles are more toned, and you'll see results in your posture. As you become leaner, your hard work in toning up your core muscles will be much more visible. Abdominal crunches and variations on crunches are effective and easy for most people to do.
Perform cardiovascular exercise. Walking, running, swimming and biking, or participating in exercise classes, will develop your muscles in different ways than strength training. All these exercises will strengthen your cardiovascular system, burn calories and boost your metabolism. Aerobic exercise is essential to achieving a lean look.