The most important thing when calling for emergency assistance is KNOW YOUR LOCATION!! Many people have the misconception that the operator will know where they are. This is usually not true. While landlines do show your location, cell phones do not. SOME cell phones can be traced to an approximate (not exact) location, others can not be traced at all. IF you do not provide the operator with a location it will waste precious time.
Another important tip is to let the operator lead the conversation. They will ask you the questions they need to know the answers to. They do not need your whole life story. Keep in mind there are other people calling with emergencies as well so the call should be short and to the point. The emergency responded will assist you further when they arrive.
The third tip I will share is to know what constitutes an emergency. Many agencys have a seperate line to call for "non-emergencies." Although somethings may seem like an emergency to you, some calls such as noise complaints or crimes that are not in progress should be handled by the non-emergency line.
Please remember that anything that is putting someone in danger (including health related problems) should be directed to the emergency 911 line.
Also remember to try to remain as calm as possible as well as cordial to the opreator. Remember the operator is doing their best to get you help as quickly as possible.