"The Civil War Inside My Brain," by June Silny over at Additude is a sweet little slide show for when you can't find the words to explain what it's like to have ADHD. I find the article especially helpful for adults with ADHD.
For adults in relationships with ADHD-diagnosed adults, whether that means romantic, work-related, or familial, #7, "Tough Love Doesn't Work," seems particularly important:
"Telling us to suck it up and try harder is like telling a visually impaired person to see harder. You can't see what he sees; you trust him when he tells you the world is a blur, and you let his glasses do their job. It's the same with ADHD. Trust us that we would fix our symptoms if we could."
In my coaching of adult clients, we'll work together on how you can communicate your needs as an individual diagnosed with ADHD. Your family, friends, and colleagues should understand your diagnosis and needs, and, more importantly, you should understand yourself.