Good job and the detail!!!! You put a lot of work into this and for those who know little about photography can use this guide and easily create great picks. It took me a long time to get my head around apertures when i was learning photography, small aperture # equals wide aperture and less depth of field etc. For the thirds you explained it fairy well. The reason they use thirds is to do with us having two eyes in our head scanning the picture. Just put the middle of first thing you want people to see in the third lines intersects. I see in one of your photos you could have moved the car up a little and centred the intersect in the middle of the car and improved the shot yet again. All in all you have done a fantastic job and probably inspired a few to take up photography.