Another thing Id like to add to what James has said, or rather clean it up. Look where you want to go. Not at the ground right in front of you. But where you want to go. Here is another thing. And Im totally guilty of doing this. Obstecal on the track or trail of course your looking for them. However you dont want to look AT them you want to identify them and then look for the way around them. Its called target fixation. If you look at, what you really want to avoid it is inevitable that you will run into it.