TPaine's list was great - I just want to add two more things to it:

Make certain you keep an updated address book of friends and family. It will make things easier for your surviving family, and it will make certain that noone you loved will miss the opportunity to "say goodbye" or to grieve with others at the funeral. (Yeah, this is an active process, not just "funeral planning" - but it would have made arrangements much easier and caused us less stress and strife - plus I am worried that I have missed a friend who was close, but of whom I was unaware of).

Make certain that your family knows your wishes for the funeral/services/burial (or cremation) - put it in writing so that when grieving-family-members object to actions made by those-who-are-in-charge-of-final-arrangements, there isn't a hassle or an argument (family making arrangements don't need vehement objections from those who "know better").

Jennifer