You're 'vibration' is the basically your state of being and awareness. Your vibration is 'constructed' of your thoughts and attitudes. So if you're happy you might say you're of a high vibration, and if you're sad you might say you're vibrating low. Someone with high awareness of themselves and the universe are generally of a high vibration. Those who are judgmental and close-minded are of a low vibration. Like attracts like, so your vibration is very important to you.