Government support of this religion indicates there is a carrot/stick involved. Whether it's accepting your place and being reincarnated upward, or not being a content caste member and going to lower form; or a system like "give unto Caesar what is Caesar's" (taxes, duty, earthly things) and be rewarded with a trip to Heaven in the afterlife.
Perhaps your carrot/stick would be a quick, painless, "happy" death or a long drawn out miserable death. I'm sure some devout priest doctors could discreetly arrange either scenario with the right drugs. Then it would be a lesson to all and confirm the belief system.
As L.Dutch suggested, different incarnations would be helpful as well. It's only the middle-aged and older that can sympathize with the gift of mortality, younger folks and children would need incarnations more appealing and appropriate to age. Easter Bunny type is easy since it's about loss, getting older. Halloween is definitely going to work there, just come up with a god (manifestation of Death) that rules on that night. Either solstice works depending on how you frame it. Now what is going to be the Santa Claus of Death?
These "spirits" in our culture teach a lot of lessons for a cooperative, social culture such as generosity and dealing with loss; that's why I mention them and not to merely replace what we have, and they are age-appropriate to build up to a more sober understanding of the high god.
Mealtimes are easy to incorporate Death since everything we eat was alive then killed in harvest. I suppose it may be interesting to speak of the one vital thing we consume that does not partake of that cycle: water. Neither alive or dead. Same goes for air sort of, if you needed it for a story device.
The more I get into this the more it seems we already worship Death in many ways. The whole "this life is suffering" and a blessed afterlife are so common to our cultures. A good life is often characterized by dying at home surrounded by family and friends while a bad life leads to a miserable lonely death with no one to care.
Is a person's death in your story a final death, no afterlife, or not? That's important but may be tempered by focusing on the manner of death. Perhaps a forgiveness center (prison?) where people without family can go to have a good death. If it's a final death (into oblivion), they would have to be vigilant about infiltration of other religions that promise all the good stuff after death (it's a fairly popular idea). Humans have already thoroughly explored the ways to give public miserable death like being hung, drawn, quartered, broken on the wheel, burned, etc. Ah, maybe the water thing can come in here, instilling a belief that drowning is the worst and using water torture for punishment. Parents and schools could even use a mild form of it to instill a base fear of a bad death.
There are already good appeasement of Death examples in monasteries such as silence and isolation. Foodwise for animal products and slaughter we have kosher and halal and whatever complex superstitions the Chinese are guided by. Those are great ways to control the population as they have to get the proper blessing in order to eat. Agricultural products could have similar codes. Then you have ceremonies like blood and bread, no that's taken, um... darn it, maybe we do worship Death to some degree. For sabbath days silence and isolation seem easy rituals, perhaps mourning or emotional detachment. Got to have churches underground or otherwise tomblike, obviously. Opium as a numbing, deathlike stupor for rituals. Competition could be for where your remains are entombed (yeah we already do that) with the grandest places being made of stone coffins like they are bricks or surrounded by clay encased corpses like the Chinese Terracotta Army.
I'm don't know if you are familiar with east asian ancestor "worship"? It's something that westerners don't comprehend the power of, the responsibility every individual has to his ancestors for every action taken. They are an omnipresent super-conscience. If someone is cast out of the family, disowned, they lose the right to that connection (I'd be relieved but I'm a westerner so don't get it) and this can be the source of great anxiety. To be alone not only on the outside but the inside, too. Mormons also have some tricky after death things people can do such as "proxy baptism for the dead" or "posthumous proxy baptism". They dunk someone in water (death's liquor, not organic) in the name of anyone dead of any time or religion, doesn't matter. They probably have baptized Genghis Kahn already.
But if your government kept the "Book of the Dead" then people could work to elevate the status of their ancestors or add to their own eventual ranking among the dead. Instead of saving for college, one may wish to give their children 10 Death Points. This would be sufficient along with the dietary taxes to fund your religion and the government. The ancestor deal of SE Asians is already a good suicide deterrent but if an added penalty of 500 death points was assessed on the family it would be highly taboo and families would go to great length to cover it up.
You may wish to look into Aum Shinrikyo, the Japanese death cult that gained strength in the 1930s (giving us Banzai and Kamikaze and a ferociously brutal military, as well as regular citizens being expected to willingly give their lives for any benefit to the homeland). It means "supreme truth" and these are the same guys that staged the sarin gas attack in Tokyo in 1995 and are believed to be hiding out in Eastern Europe where they are attracting followers of many ethnicities. Followers are encouraged to donate all earthly things to the cause and prepare for their victorious deaths.
There is also the Indian Hindu practice of Samsara when the elderly (Brahmin caste) are encouraged to pass along all their wealth and possessions and seek enlightenment or at least endeavor to disregard the "things" of life, see beyond the Matrix, so to speak. If you die humble then you get an extra big bonfire upon your death and cremation. In some places followers cover themselves in ashes, like Catholics putting ashes on their foreheads on Ash Wednesday of Lent to remind them of their impending deaths (and to get ready). The early Jews also used ashes, symbolizing Death, to repent of their evils. So Death doesn't have to be manifest in any evil way. It is the cleanser, like water (again).
So looks like everyone's already taken most good ideas for Death worship. The only thing I can offer is that "Book of the Dead" and a ranking system.
p.s. If any of you editors wish to shorten this entry, please go ahead!