You should have the analyse the breath in parts:
- Start of the in breath
- acceleration of the in breath
- peak of the in breath
- deceleration of the in breath
- end of the in breath
- start of the momentarily gap
- review if the mind wondered away
- effort and determination to keep focus (no verbalisation or visualisation)
- end of the momentary gap
- Cycle starts again for the out breath
- Continue from the start again
When micro analysing it does not wonder away. Then this will at some time become natural in which case you drop reviewing and determination and just watch the process. But when you start each session it is good to have reviewing and determination for sometime before dropping it regardless of how second nature staying with the breath has become.
When your mind wonders away and your mindfulness and equanimity has lapsed you have started creating verbal fabrications. Anchoring the mind is to stop creating verbal fabrications. When new fabrications are created there will always be some sensation associated with it (pleasant, unpleasant, neutral). When you realise that your mindfulness has lapsed, 1st realise it, examine your body and mind staying with the sensation with equanimity for a short while (few breaths) or until the tenseness has gone (at later stages this happens instantly - when you look at fabrications the fabrications pass away), which ever comes sooner, then return to the breath.