I see very many photos taken of upright stones using the phone app in portrait mode. Due to the nature of wide angle phone lenses at the top of the phone and the average height of adults using the phone angled downwards, most of these photos show a large amount of keystone distortion, which often results in blurry or difficult details to read at the foot of the stones. If however people simply turn their wrists over when taking the photos (so the phone lens is at the bottom)  the perspective will be much better and the stones will be less distorted.

Just a thought that you might incorporate into your information about taking photos.