Put simply it's to pay attention to your intention.
To pay attention to what your doing in the moment at that moment.
It's easy to get caught up in the chatter of your mind that runs about mindlessly on a loop each and every day. Sometimes we're not even aware of our thoughts but if you try and sit still for a minute and think about nothing then all of a sudden those thoughts are loud and demanding of our attention.
Thoughts are like the radio on in the background all day long and it's not until your hear your favourite song on the radio that you pay attention to it. This constant background stream is like the thoughts that go through our mind every single day. We aren't even aware of them until our favourite anniversary is coming up or our dreaded stressful event and then we get wrapped up in the thoughts, pay more attention to them than previously and start to anticipate, dread or whatever feeling the event brings up.
I hear a lot of people say, "I'm too busy, I don't have time to meditate for 20 minutes a day." And I have to agree.
Mindfulness is not meditation though.
No incense, no expensive 1000 thread count Vegan, Organic overpriced meditation mat/rug/cushion (I jest!) and not even a singing bowl required! Mindfulness can be done sitting, walking, driving, lying down, exercising.. you name it and I'm sure it can be done there too.
When our attention is focused completely on the here and the now activity, then there is no other requirements than your breath, your intention, your attention, your focus and your curiousity. It's also free and that is worth celebrating!