Ten Deadly Sins in Composition

1. Subject in the middle.
2. Horizon in the middle.
3. Crooked horizontal lines.
4. Distracting elements.
5. Inappropriate light.
6. Camera movement during exposure.
7. Inappropriate focus.
8. Inappropriate depth of field.
9. Confusing subject.
10. Lack of emotional impact.

Source: http://iconicimagesinternational.com/files/Art-Wolfe-Presentation-Summary-Notes.pdf