Mindfulness is a very simple concept.
Mindfulness means paying attention in a particular way: on purpose, in the present moment, and non-judgementally. This increases awareness, clarity and acceptance of our present-moment reality.
Mindfulness does not conflict with any beliefs or tradition, religious, cultural or scientific. It is simply a practical way to notice thoughts, physical sensations, sights, sounds, smells - anything we might not normally notice. The actual skills might be simple, but because it is so different to how our minds normally behave, it takes a lot of practice.
Animals and young children are very good at being mindful, in this present moment. I might go out into the garden and as I look around, I think "that grass really needs cutting, and that vegetable patch looks very untidy". Children on the other hand, will notice the ants or other crawlies.
Mindfulness can simply be noticing what we don't normally notice, because our heads are too busy in the future or in the past - thinking about what we need to do, or going over what we have done.
Being mindful helps us to train our attention. Our minds wander about 50% of the time, but every time we practise being mindful, we are exercising our attention "muscle" and becoming mentally fitter. We can take more control over our focus of attention, and choose what we focus on...rather than passively allowing our attention to be dominated by that which distresses us and takes us away from the present moment.
Mindfulness might simply be described as choosing and learning to control our focus of attention, and being open, curious and flexible. We can use it in our daily lives as well as helping to cope with challenging experiences and feelings.