One thing I tell people when they are starting out running is to look up. Take in the surroundings, see all that is going on around. If your eyes are trained downward, you'll miss all of the small, beautiful things that make the true pleasure of being outside and giving your all. And sometimes you see something so spectacular that just the thought of it makes you smile.
Yesterday I was driving home from a class when I saw a girl on a bike. She was standing tall on her pedals, arms outstretched to the sides and the wind caught her hair and cascaded it out behind her. Her arms moved to some undecipherable rythm, her throat was upturned - her eyes cast upwards towards the blue sky. She was beautiful in her freedom, and there was freedom in her beauty. I would never recognize her if I saw her on the street, but I will never forget her. That is living in the moment, being who you are, and living life to its fullest. The wind on your hair, the sun on your face, and movement so simple and pure.
So keep your eyes up - and don't miss a thing!