Witness the objects of the mind. Patanjali calls it dhyana, meditation -- from the same word come zen and CH'AN.
Witness the objects, the contents, of the mind. Whatsoever passes before you, watch it, without evaluating, judging or condemning. Don't be for or against, just watch, and dhyana, meditation, is created.
And the second is, witness the witness itself -- and samadhi is created, satori is created, the ultimate ecstasy is created. The first leads to the second. Start watching your thoughts but don't stop there. When thoughts have disappeared then don't think that you have arrived. One more thing has to be done, one more step. Now watch the watcher. Now just witness the witnessing. Nothing else is left, only you are. Just suddenly become aware of awareness itself, and then dhyana is transformed into samadhi. By watching the mind, the mind disappears. By watching the witness, the witness expands and becomes universal.
The first is a negative step to get rid of the mind. The second is a positive step to get rooted in the ultimate consciousness -- call it God or nirvana or whatever you wish.