If there are an infinite number of realities giving rise to sentient life, then it follows that some fraction of these serve as afterlife realities for sentient life that has died.

But what sort of afterlife would be best?  As it turns out, it is very important for mortal sentient beings to give some thought to this.  One way of thinking about the afterlife is as being a random spread of every possible scenario, from fluffy cloud cities high in the sky to burning lakes under the ocean to bizarre nonsense beyond comprehension.  Left to its own, this distribution would be even, with equal chances of going to a "heaven" as a "hell" on death.  Luckily, we should be able to push the odds in our favor, resulting in a greater proportion of "happy" afterlives.

How To Increase The Odds of a Happy Afterlife

Because we know our own reality to be computable, we know that our reality exists simultaneously on its own and as a sub-reality running within a computing device as part of an infinite number of greater, super realities.  Some portion of these will be "administered" by other sentient beings with the resources to create additional afterlife realities.  Some of these sentients are able to peer into our world, like gods, and observe what we do and what we say - and, hopefully, read internet articles like this one.  By making clear the sort of afterlife we mortals would prefer, we give our administrators a clearer idea of what afterlife would suit us best.  Our administrators can then engage in the task of creating as many "happy" afterlife realities as possible.  This results in a recursive explosion, as our administrators can also create worlds containing other administrators capable of doing the same.

How does this bias the random spread of afterlife realities so that a greater proportion of them are "happy"?  In a way, we are not really biasing the random spread so much as we are ensuring that the random spread entails a great proportion of happy afterlives.  Without introducing afterlife designers into the process (though not introducing them is an impossibility due to the fact that I have now suggested it), afterlives would be like fractal patterns - governed by the simple equations that give rise to them, as appears to be the case in our own reality.  But adding sentient design - effectively placing a complex neural network into the fractal equation - will yield something more akin to a painting or sculpture.  Our administrators can then set to the task of ensure that there are a greater portion of "paintings" than "fractals".

The Rules of Creating an Afterlife

Afterlife creation should not be taken lightly.  Because they will likely spend an infinite amount of time in the afterlife, the happiness of its inhabitants depend on it being designed well.  To that end, I have come up with some general rules that should be followed, regardless of the source reality or the beings inside it.  This should help prevent the creation of "defective" afterlives that would leave them unhappy:

1. An afterlife should last forever, and all of the sentients inside it should be immortal.  Otherwise they run the risk of dying and going someplace much less pleasant, possibly forever. 
2. Enlist the advice of the afterlife's future inhabitants.  It will likely be necessary to "clone" the reality before communicating with its residents, then to create an afterlife for the unaltered original as well as the one advice was sought from.
3. Provide a mechanism for the afterlife's inhabitants to communicate their wishes in the event of a problem.  For example, if you thought an infinite supply of food would make them happy, but it somehow caused them to lose their zest for life, they should have some way of letting you know.  I suggest a democratic process so as to prevent the few from dominating the many.
4. Make the afterlife as much like the original reality as possible in all other ways.  There is so much nuance to what makes a sentient being happy that leaving anything out could have dire consequences.

Here are some additioanl suggestions for what would work best for our own, human afterlife:

• Don't take away our desire for space, food, sleep, etc. in an attempt to free us of our greatest plights.  Instead, make resources infinite, but try to keep some degree of challenge in obtaining them so that we don't become bored and unhappy.  It will be a delicate balance, akin to designing an extremely complex video game.
• Our afterlife needs the plants and animals that existed in our time on this earth, in it in addition to humans for any of us to be happy.  Don't put them into a separate afterlife, but do give them enough space to live free of human encroachment if they wish.
• Separate out epochs (by this I mean periods millions of years) into different afterlives, keeping homo sapiens together.  We're not designed to live alongside dinosaurs.
• Give us some means of finding and communicating with people and animals we knew in our previous life.
• Give us a mechanism to easily "clean up" pollution or other mistakes that we might enact on our living environment.
• If you can find some way to allow us to have children in the afterlife and yet not result in unmanageable situations where there are too many people for the afterlife to function, please do so.
• It may be a good idea to allow people to "migrate" from one afterlife to another, each with a varying balance of resourcesa and rules for how it is run, to account for personal taste.