The most common misconception about meditation is that it requires you to clear your mind completely so it will be just blank. Mindfulness meditation is actually the opposite because it requires us to be aware of all the thoughts that our mind is generating and intentionally bring the attention from those thoughts to the present moment. What is always present? Our body. Our breath or the myriad of sensations on our body become the focus of attention instead of being caught in the story of a thought.
Mindfulness is " paying attention, on purpose, in the present moment in a non-judgemental way". The default state of the mind is not the present but the past or future. It means that we need to make a concious effort to bring our attention to what is happening right now. It's simple and yet difficult to do. But the price of not doing it might be missing all the little moments that make our lives more enjoyable.