Summarize this article:

Building your chest muscles can make breasts look firmer, perkier, and bigger. Many women, even highly physically active women, neglect working their pectoral muscles. Engage in exercises that focus on your chest in order to enhance your breast size.   Push-ups. Lie face-down on the floor and place your palms flat on the ground underneath your shoulders. Push yourself up into a plank position, keeping your spine straight. Lower yourself back towards the floor, without letting your stomach touch the ground. Try to work your way up to 15 repetitions.  Chest presses. Lie flat on an exercise bench with a dumbbell in each hand. Start with your elbows bent, so your arms are at a 90 degree angle from your body and the dumbbells are at shoulder level, parallel to the ground. Push the dumbbells straight up until their sides touch, then lower them back to the starting position. Do 3 sets of 10 reps. Dumbbell flyes. Lie on the floor with a dumbbell in each hand. Extend your arms out to the sides, in line with the shoulders. Bring your arms in towards each other (as if you were giving someone a big bear hug) until the the weights touch, then lower your arms back towards the floor. Do 3 sets of 10 reps.  If you have the time and money, consider talking to a trainer at a gym. A trainer will be able to expose you to a variety of exercises that focus on the strengthening the chest. A firm, toned core can help your stomach and hips look slimmer. This can make your breasts look larger by comparison. Try to do exercises that focus on building your core 3 to 4 days a week.  Exercises like crunches and sit-ups can help to tone your ab muscles and keep your waist looking trim. Planks are also an excellent exercise for engaging the core muscles. Activities like yoga and Pilates are excellent for strengthening the core muscles and helping you to look lean and toned. Look for classes in your local area, or try doing them at home with the help of a DVD. You can also find instructional videos online that show you how to do a variety of yoga and Pilates poses. Improving your posture and balance can help make your breasts look larger. Work on improving your posture if you want to enhance the appearance of your breasts.  Keep in mind throughout the day your back should be straight with your shoulders held slightly behind your chest. Put up reminders throughout your house. Tape up a reminder on your fridge. Have a reminder stored in your phone.  Always keep your back straight and your shoulders back. When sitting, distribute your body weight evenly in both hips. Bend your knees at roughly a right angle and keep both feet flat on the floor. When driving, keep the seat close to the steering wheel to support the curve of your back.  Keep your back curved when sleeping as well. Avoid sleeping on your stomach. If you sleep on your side, do not draw your knees to your chest. Use a firm mattress that does not sag.

Summary:
Build your chest muscles. Tone your core. Improve your posture.