For me, it's mostly a case of focusing on my breathing while "loosening" various areas of my body one by one with each outward breath, then doing my best to remain in that calm "no verbal thoughts or judgements" state

The "focus" is like when you're in a state of alertness, but without the adrenaline - purely letting the input of all your senses come in without your brain storing or processing the data, just monitoring what's happening live and in the current moment