My first question is, do you really have ADD? Cuz I gotta tell you, it's hugely over-diagnosed (esp in kids). Not being able to organize a room isn't "attention deficit," it's "life." As in, just too busy. That's my first question.
To help out:
http://www.add.org/
http://www.webmd.com/add-adhd/guide/adhd-tests-making-assessment
Read all 3 pages on this one; diagnostic criteria on pages 2 & 3

Second, if it turns out that you do fit criteria, then yes, there are non-pharmacologic forms of treatment. My cousin actually did fairly well, but it took a very determined mother and several years of treatment. Even then, he was a terminally poor student until he blossomed at the start of college (as in, C's and D's up to A's). Not sure what she tried, but I can try and find out if you PM me.