Mindfulness is the ability to stay focused on the present so you do not become overwhelmed with stress or other emotions.

People often achieve mindfulness through meditation, yoga, exercise, creativity, breathing, prayer and other calming techniques. 

Mindfulness has become a trend within the mental health world because of the increase of modern technology keeping us engaged in work.  This skill teaches you how to focus on what is going on in front of you instead of worrying about past and future issues. It also helps you take a non-judgmental stance on yourself and the current situation.  

Resources on Mindfulness
Mindfulness Can Literally Change Your Brain by Christina Congleton, Britta K. Holzel, and Sarah W. Lazar. Harvard Business Review. 
How To Make Your Mind Happy According to Science by Eric Barker, TIME
Is Mindfulness Good Medicine 
by Hal Arkowitz and Scott O. Lilienfeld, Scientific American
How Mindfulness is Revolutionizing Mental Health Care
 by Carolyn Gregoire, Huffington Post