Simply put, mindfulness is an approach that encourages being present in the moment. It can be done as an intentional practice or just by doing your best to be in the here and now and not ruminate on the past or worry about the future.
Mindfulness is often integrated into many of our other practices. There is evidence that it can elevate results in the area of self regulation, managing emotions and sharpening focus, based on the positive changes it can have on the structure of our brains. It can help us to access that slight moment in time we may need to allow us to respond instead of react.