My son struggled in school since the 2nd grade. He has been diagnosed with Auditory Processing Disorder. He has had many of the organizational issues and concentration issues you described. We found a combination of therapies to help him. He is 13 now and is doing really well. He has had speech therapy, some emotional therapy to learn to control frustrations. We try to limit empty carbohydrates and keep him well hydrated. Drinking lots of water helps to keep him focused. Believe it or not, XBox360 Rock Band has helped him too. Something about the coordination of the sound/beat, visual beat and hitting the drum at the same time seems to be rewiring his brain or making ear/brain connections. For several years, he had morning flax seed oil in oatmeal or yogurt for Omega 3s. He also takes a supplement, Elevate Brain & Eye Learning Memory Supplement by BioSource Naturals which is on Amazon.com.
It contains Amino Acids, Minerals, Vitamins & Herbs for brain and eye support. They are capsules, but they open and are tasteless in yogurt, applesauce and pudding. I am a Doctor of Naturopathy and formulated this product after 6 years of research and trying to help my son. After a month of taking it, I was getting raving emails from his teachers.