Using Photoshop

This pictures shows the composition rule "lines." The hands, the wood, and the drill are all going to the main subject. The subject is the two showing teamwork by drilling the wood. It isn't exactly clear if it is the boy or the drill, it could be both because it is all connected. I could've backed up a little bit more to fit the boy as the main subject, or got closer to the drill to make that the main subject. 

This one could show the rule balance, between her and her work. The subject is the girl taking notes. It isn't clear if we should be looking at her or what is on the computer. I could've gone to the other side of her and focused the camera on her instead of being behind her. 

This one doesn't exactly have a rule. It could be balance or rule of thirds. The subject is the boy on his phone. I could've turned the camera more to focus just on him and his face.