re: the "I'm not good at art" statement you hear from older students...that has to be nipped in the bud in elementary!!! My students are not allowed to use that phrase. Over and over I tell them....it is a matter of how much you do it. If you worked on your art skills the same way you worked on your writing or math skills...you would feel more confident. Also it is a matter of creating a safe environment where students feel comfortable taking risks and putting their work out for critique...no matter what skill level. Also it is important for a teacher to be able to say something positive about every work and help the student work from his/her strength. But...the most important thing is to tell them that not every piece they do in art has to be a masterpiece...that much of what they are doing is learning...and practicing and then..it takes the pressure off.
Hope that helps! It also shows what influence elementary art teachers have over their students. This is really where students either gain or loose their confidence!