In a traditional monastery, monks spend time on walking meditation as well as the more traditional, seated meditation that one might think of.
In walking meditation, you focus on the walking itself. You can focus on certain aspects. I like to focus on my feet hitting the ground, feeling the contact with the floor going from heel to toe, heel to toe. You are not walking to get anywhere, so this meditation is done best by walking around in a loop, or up and down in a straight line.
Since you will be walking in circles and probably at a slow pace, its good to do this someplace where you won't be seen by too many people. I chose to do this in my house, pacing around my own living room. I actually found myself details and crevices in the carpet that I had never seen before, even though I've lived in this same house for almost 20 years of my life.
"Literally having no place to go makes it easier to be where you are"
Adapted from: Wherever You Go, There You Are by Jon Kabat-Zinn