Hi Purple Planet,
Just to add another voice, as you asked for:
I find that most exercises for mindfulness are more about establishing mindfulness and getting centered. Once my mindfulness is established, so long as I stick to wholesome activities (not indulging sense pleasures, incl thoughts) then mindfulness stays strong with only minimal maintenance from a little tiny part of my mind that just looks at the situation fully. In a conversation, if I start to feel less than fully engaged, that part of the brain may note "distracted" and once I return to fully engaged I can let mindfulness run on semi-auto-pilot. I find it a balancing act: not enough intention to maintain mindfulness, to stay engaged with the moment, aware of the appropriate object of awareness, and mindfulness will deteriorate rapidly. Too much intention to maintain mindfulness and attention is not on the appropriate object because it is on mindfulness itself.
The best way to work on this is to meditate a couple of hours a day (30m morn, 60m afternoon, 30 evening is my routine on a wholesome day). When I can do this, my mindfulness tends to stay strong throughout the day. Otherwise, it takes a little more effort and deteriorates over the course of the day. However, if you can not meditate that much, just keep meditating as much as you can, and remember to re-engage with the moment when inattention arises. Its a practice.
Mindfulness killers: TV, internet, talking (instead of listening), studying facts instead of mind-body processes, thinking about food, sex, or money. Anything that stirs up passion creates a distracting force, making it hard for mindfulness to keep attention on the appropriate object.
Sotthī hontu nirantaraṃ - May you forever be well.