Create your family (1-2 young adult or adult sims). Move them into an empty lot and build them a house. One by one, you must "kill" each sim that comes onto your lot. The easiest way is to build a pool, then once the victim has gotten into the pool you must incase it with either a wall or a fence. This ensures that they won't get out. There are numerous other ways to do this, but this is the easiest.

Rules:
1) You can not use the death cheat
2) Once your sim(s) has passed, you must have the tombstone placed outside of your house to toggle ghosts (It will take some time for a ghost to appear, so be patient)
3) You can not add ghost sims to your household
4) if you use a pool as your murder weapon and your grim reaper gets stuck and can't "reap" your sim then you can use the reset cheat. The sim will be dead and a tong stone will appear