If you drop the muscle tension of the neck and shoulders, those area will loosen up, you get more space around your upper back and this leads to further relaxation of your head and face.
This newly gained “physical space” draws your focus away from unwanted thoughts and emotions, which in turn enhances your awareness of the other senses through your body;
Now start to listen, smell, look (but without projecting thoughts on what you see) and sense the surrounding.
Remember: all senses are equal (and yet, you have the choice to focus on one at the time).
This is something you can do anywhere, as long as you do not discriminate the difference between the sound and smell of (for example) walking in nature after it has rained or sitting in a city transportation going underground.