How not to alter breathing in Anapana meditation? When I practice Anapana meditation,I often get a feel that I tried to alter my breathing instead of observing natural breathing.So,how can I observe natural breath?What are the best tips for this?
A simple and natural way to relinquish breath obsessions is to count your breaths. This is a traditional Zen meditation practice that I still use 4 decades after I learned it. It works because it gives your grasping mind something to do. It's actually quite difficult to maintain a count. One has to relinquish distractions in order to not lose count. And that is actually why breath counting of any sort is initially effective.

With extended practice, the counting itself becomes a distraction since it engages the verbal processes. In the meditation practice guide of MN44, we have:


  MN44:17.2: “Verbal processes cease first, then physical, then mental.”


So to deepen the practice, we have to relinquish the numbers. One way to do so is to switch to something like prayer beads where the counting is relinquished while retaining the mindfulness of the passage of time. Or one can simply follow the breath in and out as recommended by the suttas.

Consult with a meditation teacher for individual advice on breathing.