In many teachings on mindfulness there will be the phrase: watch the breath.

There is something more important than watching.
What is more important is that the breath supports the body. In the sutta it reads having the breath be such that is calms the body. That means investigating the body for areas of tension, and using the breath with a sense of compassion and understanding to breathe for the support of those areas.

If taught wrongly, there can be the practice of watching the breath while the body agonizes. This misses the teaching of the breath being a supportive mechanism for that agonizing. Persistence means that the effort needs to be even. Once an effort that is supportive is even, it can be sustained. If it can be sustained, that is likely to bring about a mindfulness and wisdom that is also even.

Most of the time, we experience without even knowing we do. The benefits of knowing what we experience are powerful. Once we know that what we experience is painful, there can be compassion for that experience.
Sometimes an experience is too difficult to experience. The mind does not or is not ready to experience it. In that case, there can be the experience of not wanting to experience. And one can sit with that experience with acceptance and support.

Once we dont know that an experience is painful, there can be cruelty and the experience can get buried. Underneath of layers of clinging, becoming and actions, there can be an original experience that got lost. And often, an experience that is lost, may still be found much later in life.
Source: suttacentral.

If the mental state is in a state of worry, there can be mindfulness: the mental state is in a state of worry. One thing we focussed on is remembering how stressful mental states like this arise dependent upon conditions. If the breath is tense, that can be a condition dependent upon which the mind becomes tense.

If there are experiences which the mind does not experience, there is absent-mindedness. The breath can be tense, but if this is not experienced it is difficult to even it out with mindfulness of the mental state.

In contrast, a happy mental state arises. And there can be mindfulness of the conditions supporting that mental state: lovely surroundings, music, and there can be deep mindfulness of the experiences that with continued practice become blissful.

The One-minute practice is path of the fourth base of mindfulness: contemplating the nature of phenomena.
The practice is about seeing impermanence as an integral part of letting go and happiness.

Death is not in a decade, not in a year. It is always on a today, in a minute and even every moment. A human life usually lasts about 80 years. In this exercise, I assume that life lasts a single minute. If life consists of a single minute, what is important then? What must be contained within that one minute? And for what is there precisely no place? After every minute, a small death follows, and there is a new minute again. The way in which one minute is shaped determines how the next minute arises. In this way, the temporal dimension of what is known as dependent origination is practiced.

If life lasts a minute, can I react to sounds outside with anger? Or do I want to be able to fully hear the depth of sound for one last time? That is to say: experiencing the sound as sound. Without anything added to it. And if life lasts a minute, what do I want to have with me? What must memory be able to provide? The love of loved ones, friends—that must be present. Painful events, visions of the future, the past, can try to proliferate in the minute. But whoever wishes to do justice to what is beautiful and good must remember to let these things go. That which was unjust is granted the grace to disappear from the stage of a minute. There is no place to assign it in that one minute.

A minute can seem terribly short. At the same time, this practice is a prelude to what is reality, namely that life always takes place in a single moment. Whoever practices the minute subsequently finds themselves in the practice of the moment. The moment constantly falls victim to distractions, is subjected to violence, often under the guise that it is a preparation for a future. But the moment was the only thing that existed. The future was in that moment, was communicated in that moment. The past was in that one moment. The whole of life up until that point, the body, mental representations, experiences, intentions, and awarenesses—they all had been in that moment. And so the focus starts on how we can cultivate and prepare for the very next moment.

This has been an important insight for some participants. Meditation isn´t just about developing wholesome mental action. The Buddha also taught wholesome bodily action and wholesome verbal action.
If we try to cultivate wholesome mental action, there can be distractions relating to some story we tell about ourselves. Stories about having to do something tomorrow, about some past, and these can a person in the loop. The only way that changes isn´t just to cultivate compassion mentally. It is also to dramatically change the narrative we write about ourselves and others.

One of the first things that is relevant for this starts with perception. Perception is immediately written and part of these narratives. The perception of people outside the meditation space making noise, it can be a source of stress if the narrative is: these people people mess up the meditation. If the narrative can change to wishing people outside joy and happiness, imaging loving-kindness for them, the perception starts to change. Alternatively, there can be equinimity, understanding stuff like that simply happens dependent upon ignorance of experience.