Don't be bashful! If you want comments, give comments. You don't need to be an expert photographer to express your opinion about the work of others. You don't need to go into great depth. A simple remark about cropping, composition, color, subject matter, etc. can be of just as much help to a budding photographer as an in-depth critique.
Lighting is one of the most important and difficult parts of photography because it has such a huge impact on your final image. To practice what you have learned in this chapter, bring your camera outside and take a detail shot of an automobile. Perhaps there is a part in the engine bay you find intriguing, or maybe the car you choose to take a photo of has an intricate chip in the window. For this photo, use only natural lighting. You can, of course, use a diffuser, a reflector, or block out direct sunlight if you feel that makes your shot a better photo.