You will need to know your location or the address you are at.
Answer the questions as the dispatcher asks them, do not try telling long drawn out stories.
Stay calm and do not yell at the dispatcher. Even though they are asking a lot of questions, other dispatchers will already have emergency units responding, and you answering the questions will not slow down response.
Dispatchers will question you about the call so they can provide the emergency responders with the most accurate information to assist them in being prepared when they arrive.