Okay, this is for everybody, but mostly for those that are finished with assignments and are waiting for the next thing because you don't really care about lenses. I have been giving you all feedback on your assignments as they come in, so now it is your turn. I realize that in the beginning people feel like they can't give feedback because they don't know enough. Or they know if they like, or don't like a shot, but they don't know why. Well, now you have some tools, you know how the aperture, shutter speed, and ISO, affect the picture. So when you see something that just doesn't keep the subject in focus and notice they are using an f/1.4 maybe they could stop it down (this is a common term) a bit to get more of the subject in focus. If you notice some blurry shots and see that they have a shutter speed of 1" (thats one second), then they probably didn't use a tripod and they need to speed up their shutter, either by lowering their f-stop or by raising their ISO. You also now know the basic composition rules to help you talk about what is good or bad in a shot.
I think one of the best ways I have learned what makes a good shot, at least in my opinion, is from leaving comments on other peoples' pictures. I am in a few forums where I have the opportunity to comment on pictures frequently and as you do you learn just as much as by shooting. You see things people do that you really like, or things that you want to always avoid. You see a shot that you didn't take, so you don't know what they were planning on doing, only what actually happened.
The next assignment is to go back and leave Constructive Criticism on as many of the previous assignments, by other people, that you have time for. Remember when giving criticism you should find things they did well and things they can improve on. If you always tell people what they did wrong they won't want to listen to you after a while. If you always just say, nice shot, they never learn what they are doing wrong. Plus it helps you to learn to be able to put down in words what is good and what is bad. I update links at the bottom of each post to the assignments I have received as I get them, so you should be able to see them all from there. Have fun.