8. Point of Focus
It is imperative to consider the actual point of focus when working close-up with tiny subjects. You can dramatically change the appearance by where you chose to focus. These two shots of the same teasle head were both shot at the same maximum aperture, but the point of focus was changed by a couple of millimetres to produce an entirely different effect.
Teasle head. Nikon D200, Sigma 150mm macro lens. 1/320sec @ f/5.6, ISO 100.