This technique helps me break a thought pattern. I ask myself (regarding my situation
where I physically am right now and then expanding outwards to my life)
“Is this pleasant?”
“Is this unpleasant?”
“Is this neutral”
For example, I walk into a room thinking about work, sit down still thinking about work, and finally notice I’m thinking about work, so I ask myself the questions. Is the chair alright? How do I feel? Hungry? Cold or tired? No, this chair and room are comfortable. I’m safe, my family are nearby, I just ate a nice sandwich etc... that’s pretty good.
It forces me back into the present. Added bonus, the moment you label anything as neutral it transforms into pleasant, because anything not unpleasant is pleasant!
You could try it continuously or set alarms or just ask yourself often. Whatever suits you.