You know this already; that the “father of modern mindfulness” Jon Kabat-Zin, says that mindfulness meditation “is paying attention in a particular way: on purpose, in the present moment, and non-judgmentally.”
The reason I’m bringing this up (again), is to focus on one of the elements of this definition today: the non-judgemental part.
Because for most of us, the non-judgemental mindset is not a destination reached overnight, and can cause grief for many a mindfulness practitioner. Especially as almost all of use have been trained in an extremely judgemental (=competitive) schooling systems.
So the non-judgemental, accepting part of mindfulness meditation will require a possibly long time of noticing the judgements in your mind flying thick and fast.
Observing them is the key here. It’s as simple as that.