you've had superb (and practical!) advice already, so i'll just drop in one more little thing that has worked for us. like HappilyMom, we have a list of family rules (it's eerily similar!) but we also have a list of responsibilities that sits beside it on the fridge. we had to do this pretty early on with our manipulative little one.
it clearly outlines how each person makes their specific contribution to the family - we literally went over with DD exactly how it all breaks down and copied it out for all to see. so for me, it's things like working so i can pay the mortgage, doing all the cooking, driving and (now) the homeschooling. for DH, it's working so he can cover all the other bills, and doing all the cleaning and yard work. for DD5, it encompasses chores, morning and nighttime self-sufficiency, packing/unpacking her dance and swimming bags, etc. it's quite a flexible list, and we always edit it together as our needs change.
for an ADHD situation, i'd imagine that a LOT more scaffolding would be in order, but the core of what worked for us was identifying that each person was expected to make a contribution to the way our family functions. DD suddenly stopped seeing herself as an entitled freeloader (hee!) and it has made a really, really big difference.
