Ask Before you Help
Interact with the person as a person first! Just because someone has a disability, do not assume he or she needs help. Offer assistance only if the person appears to need it, and ask how you may help before you act.
Be Sensitive About Physical Contact
Some people with disabilities depend on their arms for balance. Grabbing them - even if your intention is to assist - could knock them off balance. Avoid patting a person on the head or touching his wheelchair, scooter, or cane. People with disabilities consider their equipment part of their personal space.
Think Before you Speak
Always speak directly to the person with a disability, not to his companion, aide, or sign language interpreter. Do not apologize if you use an expression such as "I gotta run" or "See you later" that relates to the person's disability. These expressions are part of everyday language and, it is likely the apology will be more offensive than the expression.
Do Not Make Assumptions
People with disabilities are the best judge of what they can or cannot do. Do not make decisions for them about participating in any activity.
In the movie "I am Sam", the main character, Sam, is an adult with a developmental disability. An initially insensitive attorney says to Sam:
I need that list of names from you—people who can testify that you're a good father despite your handicap. I didn't mean your handicap, I meant your disability. [shakes her head] The fact that you're retarded. That's not the right word. [exasperated] I don't know what to call you!
To which he replies:
Sam. You can call me Sam.