Let of all meditation strategies .....including meditation itself
Notice sounds and sensations not strategically. As you happen to notice them, just let your mind be the space in which they appear
The term "not strategically" has a deeper meaning than appears at first. iOne of the stations in the development of Mahamudra meditation is the ability to let go even of everything related to meditation.
This means that meditation simply becomes "the view" of non-duality, the view of the natural mind where nothing needs to be changed, suppressed, made to happen etc.
Everything in this stage is let go of. For example, at this stage, concentration is a strategy. Or, intentionally "easing up / intensifying"
Not doing any meditation strategy is one of the characteristics, eventually, of the "meditation of non-meditation".