These photos are successful because you can see the main focus of each photo.
(Direct and diffused lighting)
These pictures are successful because it looks like the organisms are smaller than they actually are.
(Direct and Diffused lighting)
Rule of Thirds and Freeze Actions
This picture is successful because you can see him skating past as freeze action.
Freeze Action and Direct Lighting
This photo is successful because you can clearly see she is spinning because of the direct lighting