We close our eyes and focus on our breath without any visualization or counting. The idea is to remove as many distractions as possible and become aware of what "is"; breathing is something that we experience every moment. Another big advantage is that it doesn't associate itself with any sect or religion -- everybody breathes. It is true that an experienced meditator can meditate with his eyes open, while walking, etc. but the beginner should remove all the distractions and sharpen the concentration first.