Presence is the most ordinary thing and the thing most often missed. One is rarely here; one is rehearsing the next moment or rehashing the last. The contemplative traditions diverge on metaphysics but converge on this: whatever else is true, attention given to what is happening now is corrective in itself.
Different traditions name it differently. Buddhism’s Mindfulness is its most technical description. Eckhart Tolle popularized it as “the power of Now.” The sufis speak of hudur — the heart’s presence before God. In each case the practice is simpler than it sounds and harder than it looks.