When we practice mindfulness by following our breath, the first step is to become attentive of our breath. This means just becoming vividly and clearly aware of the breath as it flows in and out of your nose. This is attention.
But when we start the practice, our mind is like a pot full of sediments and is being constantly shaken and agitated. The water appears cloudy. This means that our mind is not relaxed and peaceful because of the inner chatter, thoughts, memories and fantasies from which we create our stories and become lost in them. Taking the position of the guard at the city gate or the butterfly on the petal can help us focus.
However we are like the child who has just tried to take its first step and failed. But just like the child who tries again and again until it succeeds, we need to try and try again to attend to our mind. This means we have to become aware of when we have lost our attention and then bring it back to the breath and focus on following the breath again. This process of becoming aware that we have lost our focus on the breath is meta-attention. It is the ability to know that your attention has wandered away. Initially, it takes a lot of time to know that your attention has wandered. But as time goes, you can pick it up quickly. This is similar to riding a bicycle in a balanced way. Initially when you try to ride a bicycle, you tend to fall down and you have to put your foot down to prevent falling down. But as you practise and become better and better, you do a lot of microrecoveries without putting your foot down and you succeed in riding a bicycle with ease. In a similar way, you will be able to recover a wandering attention very quickly and often and if you can that constantly, you get sustained attention which is concentration.
When this happens, you mind becomes calm and quiet like the pot with still water with sediments at the bottom. There is clarity and joy because you have your mind in its natural state.
But to do this successfully, you have to be gentle with yourself, not critical and judging. You have to adopt what is called the mind of the loving grandmother. A loving grandmother loves you no matter what trouble you cause, she loves you as you are. She will correct you or may intervene sternly but she sees you as perfect and loves you. In a similar vein, if you have to succeed in this, you have to love yourself gently all the way on the journey.