How can I make my ADHD/LD son more organized at school?

Next school year is my son's last year of elementary school. Then he moves on to Jr High, where he will have 7 different teachers, 7 different classrooms, and 7 different homework assignments daily. I need to get him prepared and more self sufficient and organized. Currently, his ADHD and other specific learning disabilities make it hard for him to be organized. (He is not in special education classes because his disabilities are not extremely severe, but he does have an IEP which allows him certain accommodations to help with his grades.) He rarely brings home his homework and other important papers. And if he does bring things home, it is usually a few weeks after he originally received it. How can I work on this with him before he gets to middle school? I am hoping to use this summer and next school year to really tackle his organization. The school counselor is supposed to be helping him with this, but she only sees him once a month to clean out his desk and so far she hasn't made any progress improving his organization. Any suggestions?