Meditation is the only intentional, systematic human activity which at bottom is about not trying to improve yourself or get anywhere else, but simply to realize where you already are.” Simple.
Mindfulness involves practicing to solve the problem of thinking when we don't know we are thinking. The problem is not thoughts. It's being unaware and without control of our thoughts. The most common practice is to pay attention to our breathing, noticing when our thoughts stray from this, and bringing our attention back to the breath.