build a strong composition
I believe composition is the most important aspect of a keyshot. Design your image so that it leads the eye to the important parts. Want people to look at the face? Put the most contrast there. Have lines converge toward it. Pay attention to the rule of thirds: divide your image into thirds and put elements of interest where lines intersect. You can use the golden spiral to great effect; try experimenting with it at various angles. And keep in mind that a character’s line of sight will send the viewer’s eye in that direction – you can use that to your advantage.