1. I used to tell my daughter when she was skiing downhill that she should bend at her knees. The same rule often applies to shooting images. Or even to lay flat on the ground to get the best perspective.
2. Use the golden rule as a starting point, but break if the image will be better that way.
3. As in the Rod Stewart song: Every pictures tells a story - not always true. Anyway, I often have an idea of a story that the picture shall tell. Or I have a picture in my head that I like to make.
4. Be aware of the shadows or the reflections. Typically on streets or in water. Don´t leave them out or cut them in halves.
5. Look for lines in the image or lines leading towards main object.
6. Don´t have out-of-focus subjects in front of the main object if they don´t add anything to the image.
7. If your pictures are not as good as you expect - you are propably to far from your object
8. Keep your camera straight and steady.
9. Focus on the eyes - both on humans and animals - if you do otherwise think twice.
10. Light. Last in the list but maybe the most important. Always look how the light and shadows hits the objekt. In my opinion this is often the hardest part, but also whats very often makes the image. There is no rule for light, but direct light is normally not very good. Guess it is no need to say it - but don´t ever use flash.