Visible incisions or tiny microcuts that can slice through several layers of skin and are prone to bleeding.
Shaving against the grain, going over the same area without re-applying a shaving barrier, using too much pressure or a blunt blade.
Always begin by shaving with the grain (i.e. following the direction of hair growth, noting that it can often change direction). Always use gentle strokes with a fresh blade. Smoothing down the ‘landscape’ of your jaw with a cleanser or an exfoliator before shaving will also help.