Mindfulness is to shift your habitual pattern of unmindfulness and mindlessness to awareness, to being where you are, now and here.
No one can achieve this overnight. Could you learn your alphabets, or swimming, cycling, in one day? Just consistent practice, it is your deepest commitment to yourself, that you are not going to fuel that which is the cause of unhappiness in life but you are committed to REWIRE your brain, just by practicing attention, attention, attention.
Love and Peace!