To be successful ....

I define success as "staying happy". In order to be successful, or to stay happy, one has to be
1) Physically fit
2) Mentally fit

Physical fitness is to keep yourself away from disease, ailments and aging problems. Exercise helps you to keep the body fit, fight external disease-causing-agents, gives you the ability to self defend and keeps your body light.

Mental fitness simply means to keep your heart free from worries and keep your brain busy with creative ideas. An empty mind is a haven for devilish ideas. But remember that devilish ideas cannot co-exist with creative ideas. So inculcate the habit of filling your mind with solemn thoughts and you automatically push the bad ideas to the doorsteps. Meditation can help you attain mental fitness.

On the other hand, remember that "staying happy" is very different from "being happy" - former is to force yourself to be happy irrespective of what's happening to you or with you, where as later is when something happens to you and you get happiness as a result.

So understand that both physical fitness and mental fitness are needed to attain success in your life. People will follow you when you are attractive both physically and mentally. You will fall short of your goals when you lack either of these traits.

Good luck.