I’m definitely no expert on mindfulness and meditation, but I’ve tried it consistently enough, and been frustrated enough, to find that these two things in particular were useful when I was getting restless from not succeeding.
1) Try to forget the shapes of the things around you. This has made a significant difference for me. When I struggle to silence the voice in my head that identifies what my eyes see (“I’m looking at a poster on the subway. It’s an ad for some bank…”), I focus on making the shape of what I’m looking at irrelevant. If it’s a poster, I try to look at it as though I had never, ever seen a rectangle before. If there’s writing on it, I look at the words long enough for them not to mean anything — that is, until they look weird. Then I keep looking.
Another example: Today, I was staring at some mountains. I couldn’t quite ease into the situation. What helped was to look at the mountains and the sky together, at the contrast between them, so that I couldn’t focus on the fact that I was seeing a mountain. Taking in the colors (blue, green) together instead of the named things (mountains, sky) made everything new, and after a few minutes, I felt much more “in” that place.
If you’ve read anything on mindfulness, you already know you’re supposed to see things as if for the first time; but it may help to know that what often holds me back is my tendency to think: “I am seeing this tree for the first time” instead of “Wow, I’ve never seen that thing before.”
2) Don’t ask yourself how long you’ve been sitting there trying. This will only keep you distracted.
If you are stressed out and in a busy place, set a quiet alarm on your phone to go off in 3 minutes. Or 10 minutes. Whatever time you have. Stick your headphones on (and into the phone), so the alarm doesn’t bug anyone else. And now don’t look at your phone under any circumstances, and just breathe, do your mindfulness thing. Just don’t get annoyed because it’s not working and wonder how much time you’ve wasted trying this, because if you keep checking the time, you’re going to feel worse.