At it's very simplest, mindfulness is about controlling where we place our attention.
The roots of the practise are based in Buddhism and have found relevance in today's high speed, instant this, instant that world.
The elements I have found most useful and easiest to apply are,
The topic is the source of much research with many online resources, books and workshops now available. You can dip in or engage with the deeply spiritual aspects of the practise.