Read all you can about adult ADD. My favorite is "Women with ADD" by Sari Solden.
Remember that ADD is not a handicap or an illness despite the fact that society views it as a disablity. ADD is a gift. Remind yourself of this often. People with ADD are the inventors, the artists, the healers, and yes the scholars and teachers. People with ADD are in every field and it is the traits that make them "ADD" that help them suceed.
Exercise daily. The endorphins from exercise work like ritalin for me. I have about (depending on how strenuous. You have to find a balance with it so don't give up.) an hour or an hour and a half of pure clarity after I exercise. Use this time to do what is hardest for you, be it cleaning, or whatever.
Small amounts of caffiene for desperate times can be helpful especially for children and it beats the pants off of ritalin. This seems to be more helpful for hyperactive types, though.
Balanced whole carbohydrates and protiens in regular intervals throughout the day. Plenty of green veggies and fruits. Plenty of water. You can try to supplement with efa's if you don't eat fish (salmon being great brain food).
For your home, a system like flylady or www.mymessyhouse.com
can help a lot. As long as you have reasonable small goals! and doable routines! (Don't get over zealous about routines and lists. It took me a long time to learn to have short to do lists.) Can you afford a housekeeper? Look into a way you can budget for one or where you can trade for one or where you can work some kind of job/at home business to pay for it. If it takes you eight or ten hours to do what a pro can do in four hours and there is something you'd rather do that could earn the money to pay that pro, it's worth it. I know this advice sounds kind of far fetched but at least play with it and see if it is workable. Give up cable and lattes to have someone come in once a month if you can. (Weekly is ideal.)
Most of all be easy with yourself. It's not your fault. This is not something bad about you, this is something good about you. Google adults with ADD.
Oh, and I also like (for me, can't reccommend for your child) yerba mate tea. It helps me focus without making me jittery like caffiene.
gifted with ADD (inattentive)