Speak directly to them. When talking with a person with a disability, don't focus solely on their companion or interpreter.
Treat adults as adults. Address people who have disabilities by their first names only when extending the same familiarity to all others.
Shake hands. People with limited hand use or who wear an artificial limb can usually shake hands (shaking hands with the left hand is an acceptable greeting). Visually impaired people will usually offer their hand first.
Identify yourself and others who may be with you. "Hi Mary, I'm Sam and this is Joe on my right." When conversing in a group, remember to identify the person to whom you are speaking.
If you offer assistance, wait until the offer is accepted. Then listen for instructions. When assisting a blind person, offer your arm to lead them instead of grabbing theirs to push.
Give them some room. Leaning or hanging on a person's wheelchair is similar to leaning or hanging on a person. The chair is part of the personal body space of the person who uses it. Never patronize people who use wheelchairs by patting them on the head.
Get to eye level. When speaking with a person in a wheelchair or a person who uses crutches, place yourself at eye level in front of them to avoid stiff necks for both of you.
Listen attentively. When you're talking with a person who has difficulty speaking, be patient and wait for the person to finish, rather than correcting or speaking for the person. If necessary, ask short questions that require short answers, a nod or a shake of the head. Never pretend to understand if you are having difficulty doing so. Instead, repeat what you have understood and allow the person to respond. Ask the person to write down a word if you are not sure of what he is saying.
Help them understand you. To get the attention of a person who is hearing impaired, tap the person on the shoulder or wave your hand. Look directly at the person and speak clearly, slowly, and expressively to determine if the person can read your lips. Not all people with a hearing impairment can lip read. Place yourself so that you face the light source and keep hands, cigarettes, and food away from your mouth.
Relax. Don't be embarrassed if you happen to use accepted, common expressions such as "See you later," or "Did you hear about this?" "I've gotta run!" that seem to relate to a person's disability. They don't.
Practice. Don't avoid contact with people who have disabilities. You might be nervous talking to them, but as with anything in life once you get some practice it becomes second nature. Think now of some things you might say: "May I hold that door for you?", "Your guide dog is beautiful, what's his name?", "My name is Kate, it is a pleasure to meet you."
sources: Easter Seals: http://www.easter-seals.org/, The City of Sacramento ADA information Page: http://www.sacto.org/adaweb/learning_about_disabilities.htm | 
