To make a more engaging portrait; have your subject tilt their head:

John the Baptist Tilt Head

Note the tilt of his head:


Madonna con Bambino by Carlo Crivelli

Carlo_Crivelli_-_Madonna_con_Bambino.jpg

tilt eye- small - Carlo_Crivelli_-_Madonna_con_Bambino copy.jpg

The full composition of John the Baptist by Leonardo da Vinci.

Venus:

venus - Sandro_Botticelli_-_La_nascita_di_Venere_-_Google_Art_Project_-_edited.jpg

In this famous painting of Venus by Sandro Botticelli, note how Venus’ head is tilted:

tilted head venus.jpg