Jonathan,
Meditation practice is named that for a reason .. it's practice for employing the fruits off the cushion.
In practice we touch our inner calm and peace (though we may have to wade through much inner disquiet to get there). In practice we develop concentration (though we may at first become more aware of our lack of concentration to get there). In practice we develop insight (though we may have to go through much confusion to get there). In practice we develop equanimity (though we may go through periods that seem unbalanced to get there).
In developing these fruits of calm, concentration, insight and equanimity we touch these states repeatedly. We undo many old habits and, slowly over time, as we touch upon these states we develop peace and even bliss and rapture - we become aware of the
possibility of these states of mind which may have eluded us before.
As our practice bears fruit on the cushion, off the cushion we can reach back to these experiential states of mind and place ourselves in them.
If you are in a social situation and start to feel anxious you can remember (be mindful) of the states of calm, peace, bliss or rapture you have experienced and know your mind can inhabit - and induce these in yourself through anchoring your momentary experience through a few breaths.
If you are experiencing unwanted thoughts you can bring your mind to peace through anchoring experience of now in the breath, you can bring your mind to calmly concentrate on the thought and develop equanimity towards them through anchoring experience of the moment in the breath.
The breath is the anchor that allows you to embody yourself and move away from the head-centric over-thinking conditioned state that is the norm in today's world. The breath is a present moment experience. Just stopping for a few moments in the ways I described above (second para of my post you quoted) you can bring your mind back under control when it goes off track.
It doesn't happen overnight (but it can happen relatively quickly with dedication and great self-honesty).
No one can do it but you (but you are the one who can do it).
Remembering (synonymous with the Pali word Sati, translated as mindfulness - "being mindful of") these experiential fruits developed in practice and employing them in your day to day life is key. Step back from situations of discomfort for just a brief moment, breathe and remember you know how peace/calm feels, how concentration feels, how insight works and how equanimity feels. Don't remember with words, remember with your experience developed through practice.
Balance on and off the cushion is achieved this way. And as redalert pointed out sagely:
Are you observing the precepts? Observing the precepts is in my opinion the first ingredient in cultivating a calm concentrated mind.
If one is not observing the precepts the practice won't work to it's fullest extent, on and off the cushion balance won't be found.
Kindly,
Matthew