meditation - How obvious should the touch of the breath be? When I try to feel the sensations of the breath at the nostrils/upper lip during anapana, it's so faint that after a certain point, I think I may be imagining the touch of the breath.

I may even feel other sensations (pressure/vibrations) on my face but I would still have trouble feeling the touch of my breath at the rims of my nostrils or my upper lip. And my mind is still very much lost in thought so I know it's not because I've become very concentrated or anything.

So how obvious should the touch of the breath be? Should it be as faint/subtle to the point of almost feeling imaginary? Should I stick to this and assume it will approve as does my concentration?
The touch of the breath should be totally obvious and clear. 

Anapanasati is not something exactly easy to do. If it was easy to do, all of the posters on this chatsite would be enlightened. 

You should stick to it and assume it will improve as does your concentration.

You should experiment with different methods, such as: 


Place one finger horizontally under the nostrils and mentally note the thought "out" each time you feel the air touching/striking/warming your finger; and mental note "in" when you feel the air not touching your finger and being sucked back into your nostrils. 
Make sure your finger is placed at a distance away from your face where the maximum impact of the breath can be felt. For example, my finger is about 6 millimetres away from my face/upper lip because i have a big nose.





Then continue to do the same but only mentally note "out" and stop mentally noting "in". Instead, let the mind be quiet, open &amp; relaxed on the in breath; but continue to note the out breath. 
If your arm gets tired/uncomfortable, change to your other arm &amp; finger.
As your mind familiarizes itself with the sensation of the breath on the finger; then allow the mind to search for &amp; feel the sensation where it is most obvious in the nose/nostril.
Also, as you start to regularly feel the breath in your nostril, then let the eyes &amp; face relax and allow the mind to try to feel the breath in another place, such as in/through the throat. To only watch the breathing around the nostrils is not important.  
There are other methods, such as to occasionally deliberately breath a little longer and postpone/extend the end of the breath a little longer (but not too long so it becomes pranayama !!!. We don't want to get dizzy practising Hindu pranayama).   


Ultimately, the breath can only be perfectly lucidly experienced by the mind when the mind is very quiet and actually not even try to watch the breath. "Trying" to watch the breath is also another obstacle to clear knowing of the breath. However, if your mind is not quiet and has thoughts, "trying" to watch the breath helps suppress the thoughts.