For 6-pack abs, you can try some strength training exercises that focus on the abs, such as sit-ups or side curls. And be sure to balance strength training with other exercises like running or cycling to get your heart racing.
Because of your age, ask a sport coach or a gym instructor for a workout program that is right for your stage of development. If a boy’s body hasn’t finished going through the hormone changes that are part of puberty, he usually can’t develop muscles that are big enough to show. Your body needs enough of the hormone testosterone for muscles to bulk up when you exercise them.
Developing a good physique is only partly about working out. It’s also about eating well — lots of fruits and vegetables, and lean protein like low-fat meats and dairy products like milk.
But more than anything, managing your physique is about managing expectations. Only some guys ever get the type of abs you are talking about. A lot also depends on a guy’s genes. Your ab muscles can get larger and more visible if you exercise them and lose excess body fat, but not every guy will develop a visible “six pack.” That’s because the skin and tissue over some guys’ abs is too thick to let the individual muscles show through. It’s perfectly normal, and it doesn’t mean a guy is overweight or that he isn’t fit or strong.
Unfortunately, lots of people’s expectations are distorted by movies and advertising (where Photoshop can take a man from flab to abs in an instant). For a reality check, talk to your dad or an older brother about how their bodies looked when they were in their teens and early twenties.
I hope this helped.