Maintain an infinite gaze
The mind and body are wound together like the wind and the ocean. You might like to spend a few moments exploring what happens to your body when you are lost in thought - my body constricts all over the place. Another thing that happens is that the visible field disappears - we go into a thought world that hijacks the process of seeing. A fairly reliable measure of how stressed you are is to see how long you can maintain your vision on an object - if we are stressed then we lose focus fairly quickly.
So then, here's the trick. If we practice staring at an object and relaxing our gaze into infinity then we are inhibiting the wandering mind - perhaps this is why zen monks encourage this practice. Once we aware of the relaxing power of gazing into space, then we can apply the technique through out the day to calm ourselves down. Then, if we are especially practiced, we can couple gazing with our breathing and create an even more powerful relaxation experience for ourselves. If we then integrate this with the mental excitation of the purely relaxed mind, then we open up something amazing for ourselves to contemplate.
However one step at a time. Stare out of the window and let the mind relax ...