Take a deep breath, and say to yourself, "Be calm." If you are religious, offer a silent prayer for you, your partner, and the person(s) that you are about to notify, then knock on the door.
After knocking on the door, introduce yourselves and ask if they are the family you are supposed to notify. You want to be certain that these are the correct people to be contacting, the next of kin.
Then ask the resident being notified if you can enter their home. (Note: sometimes people won't invite you inside so you are left with no other option than talking to them through the door.). Once inside, if you can get the person(s) to sit down that is good, but not necessary. Because everyone is dumping so much adrenaline at this point, often people won't sit down until you tell them what is going on.
Ask as calmly as you can, and slowly while making good eye contact say, "Are you the parents of [Name]? I'm afraid that I have some very bad news for you..... (pause here momentarily to give those being notified a moment to psychologically prepare themselves). [Name] has been involved in a serious automobile accident, and he/she has died. (Pause) I'm so sorry. They did everything they could to save him/her."
Saying you are sorry expresses emotion, it makes you human. Continue to use the word "dead" or "died" throughout the ongoing conversation, and continue to use the victim's name. This helps those being notified come to the realization that their loved one has died.