The slow motions and quiet contemplation of Yoga lead naturally to meditation. Through yoga and meditation, one learns to relax mind and body.
When you begin meditation, it is best to start in a quiet room. What you're seeking first is to begin to develop enough awareness of your mind that you find yourself watching what's happening inside. Just a watcher, though, not a judge or a commentor. Developing this is easiest if you are allowed to sink into this place without outside noise. Do not, however, focus on just stopping thinking; just let it stop. Don't let the rattling on of your mind get on your nerves. Just let it roll off your back. The watching of your mind is called "Mindfulness."
One big problem with this relaxation is that while you are resting and calming your mind, letting this "watcher" come burbling out, falling asleep is a real danger. Well, not "danger" in the sense that it is dangerous, but sleep isn't the goal at the moment. If you're in a yoga stance, however, it would be more difficult to fall asleep.
Along with the sense of the mind, yoga follows a parallel path and helps with a sense of the body. Yoga helps us be more aware of the body, which helps the overall process of developing mindfulness. The two together establish solid habits of reflecting on what your body and mind are doing.
If you feel like the world never lets you breathe, if you find yourself being cranky and angry for no particular reason, if you are constantly fatigued, if your interest in sex has waned; I recommend this this e-Book on yoga and meditation.
Other things you can learn from this book: