1. Speak clearly and slowly. Rephrase or repeat your sentence if the person is not able to understand. 
  2. Do not change topic quickly. It can confuse hearing impaired individual. 
  3. Face the hearing impaired individual directly or have their attention before speaking. 
  4. If the person is having profound then use total communication like facial expression, body language etc. 
  5. Talk into their "Good ear". 
  6. Avoid talking in presence of background noise.