Start with small distractions
Look at the whole image before working on individual details. A stray object at the edge or an uneven crop may distract more than a small feature on a face. Make a short list of changes that support the picture rather than searching for something to fix everywhere.
Keep the person recognisable
Skin has texture, clothes have folds and expressions are rarely symmetrical. An edit can tidy a temporary distraction without removing the qualities that make someone look like themselves. Discuss personal preferences rather than assuming what another person wants changed.
Step back from the screen
View the picture at a normal size after close work. Compare it with the original and take a break before making a final judgement. Keep a separate original file so that an experiment can always be revisited.