Clench your fist as tight as you can. Clench even tighter. Then slowly open your fist. Feel the release of tension in the hand, the arm, and perhaps the entire body.
Now close your eyes and create a plan for “Things I Have to Do Today.” It could be buy gas, go to the cleaner, pay the bills, etc. Be clear about the sequence, the preparation and the time each will take.
Sense the tightness in your head. Now let go of that planning effort and be aware of how the tightness melts. This is opening the hand of thought.
When meditating you don’t want to stop the arising of thoughts; all you do is stop clenching. To do so, closely watch your thoughts arise, manifest, and disappear.