“In a family, if there is one person who practices mindfulness, the entire family will be more mindful. Because of the presence of one member who lives in mindfulness, the entire family is reminded to live in mindfulness. If in one class, one student lives in mindfulness, the entire class is influenced. ”
Why should you meditate? First of all, because each of us needs to realize total rest. Even a night of sleep doesn't provide total rest...

Keep your back straight. This is very important. The neck and head should be aligned with the spinal column; they should be straight but not stiff or wood-like. Keep your eyes focused a yard or two in front of you. If you can, maintain a half smile.
Now begin to follow your breath and to relax all of your muscles. Concentrate on keeping your spinal column straight and on following your breath. As for everything else, let it go. Let go of everything. If you want to relax the worry-tightened muscles in your face, let the half smile come to your face. As the half smile appears, all the facial muscles begin to relax. The longer the half smile is maintained, the better. It is the same smile you see on the face of the Buddha.
Place your left hand, palm side up, in your right palm. Let all the muscles in your hands, fingers, arms, and legs relax. Let go of everything. Be like the waterplants which flow with the current, while beneath the surface of the water the riverbed remains motionless. Hold on to nothing but your breath and the half smile.
For beginners, it is better to sit no longer than 20 or 30 minutes. During that time, you can readily obtain total rest. The technique for obtaining this rest lies in two things--watching and letting go: watching your breath, and letting go of everything else. Release every muscle in your body. After about 15 minutes or so, it is possible to reach a deep quiet filled with inner peace and joy. Maintain this quiet and peace.

Some people look on meditation as a toil and want the time to pass quickly in order to rest afterwards. Such persons do not know how sit yet. If you sit correctly, it is possible to find total relaxation and peace right in the position of sitting. Often it helps to meditate on the image of a pebble thrown into a river.
How is one helped by the image of the pebble? Sit down in whatever position suits you best, the half lotus or the lotus, back straight, the half smile on your face. Breathe slowly and deeply, following each breath, becoming one with the breath. Then let go of everything. Imagine yourself as a pebble which has been thrown into a river. The pebble sinks through the water effortlessly. Detached from everything, it falls by the shortest distance possible, finally reaching the bottom, the point of perfect rest. You don't need to know the length of time it takes before reaching the point of complete rest on the bed of fine sand beneath the water. When you feel yourself resting like a pebble which has reached the riverbed, that is the point when you begin to find your own rest. You are no longer pushed or pulled by anything.