Well, look no further! Here's an easy, step-by-step guide to building a religion of your own.
Step 1: Start General
"There is a divinity and this divinity created the universe." People are natural storytellers, and people are naturally curious about where they came from, where the stars came from, and where the ground they're standing on came from. But, people are also lazy, and don't want to spend years learning about the physical properties of the universe, or the mathematical models that describe the formation of the heavens and the earth. "God did it" is an easy explanation that appeals to folks, and you'll find that people will accept it wholeheartedly without one single shred of evidence.
Step 2: Work from the general formation of the universe to human beings
People want to believe they are special. People adopt worldviews that are inherently self-centered; if you tell a bunch of folks that god made the universe, people are going to want to know if god made them. "God made the universe with a set of immutable natural laws and then those laws took over to form, over many millennia, us" just isn't satisfying for most people. It's not a good story.
You want to tell folks that your god made them specifically. This, too, you will find accepted without question or proof; people are already halfway to believing it before you even begin, because it's a damn good yarn that appeals to their inherently self-centered worldviews.
Plus, you'll find it useful for the next step.
Step 3: Since god created human beings, he must have had a reason for doing so, right?
Human beings are inherently prone to promiscuous teleology--the tendency to believe that things happen for a purpose. It's not enough for us to look for the explanation about how things came to be; we also want to know why. This appears to be a side effect of a hyperactive sense of agency, which has a positive survival value; we see agency because it helps keep us alive. It's easy to mistake a shadow for a burglar, but people rarely mistake a burglar for a shadow!
Anyway, appealing to this sense of purpose will help reinforce your religion in the minds of the people you talk to. It's a great shot of self-esteem; "God has a plan for me!" It helps personalize your religion by appealing to people's inherent self-centeredness. And it's massively helpful in establishing the creeds you'll be using a bit later.
The notion that your god has a purpose for humanity makes the next step logical and easy to swallow:
Step 4: Since god has a purpose in creating us, there must be a right and wrong way to live. The right way to live is in accordance with this purpose; the wrong way is in defiance of it.
This is a step that's surprisingly subtle in its ramifications. Anyone who believes that your god had some reason for creating human beings is going to find this easy to believe also; you won't have to sell this point. And it opens the door to all sorts of distractions you can easily use to deflect conversation away from anyone who wants to challenge the assertions you made in the first three steps. Just bring up the philosophical idea of "free will," assert that your god wants us to live according to his plan of our own choice, and any inconvenient conversations that start to head too close to "Well, how do you KNOW god created the universe?" will quickly become bogged down in the semantic morass of free will and determinism. You can trap the conversation in this mire for decades.
But, now you have a problem. Now you have to figure out some kind of way to codify what the right way to live is, because people are going to want to know. So far, you've been able to skate along without offering even the tiniest scrap of evidence that ANYTHING you say is true; people will believe you because they want to believe you. But once you start telling folks what the right way to live is, people are going to want to know how you know.
This is a problem that's never been completely solved; look at all the other religions and you'll see that folks really like to bicker about this stuff. But there is a solution that works well enough to get you by, and that is:
Step 5: Tell people that your god writes books.
Books are awesome. You can claim that your god gave the book to you by divine revelation without also leaving the door open to other folks saying they've had revelations that contradict yours, because where's the book? You don't have to remember all the various tenets of your religion, because hey, they're in the book. You can fend off challenges to your authority by referring back to the very book that you wrote to begin with. It's brilliant!
It doesn't even have to be a very good book. It can be filled with contradictions (your god created the world, then created man, then did some stuff, then man got lonely, then your god created woman; no, wait, your god created man and woman at the same time). It can make assertions that are provably false (the Native Americans are a lost tribe of Israel). Doesn't matter. All you really need is a story that sells the book--some kind of tale that'll help people accept that the book is actually written by your god.
A story involving magical plates made out of gold hand-delivered to you by an angel is good. If your imagination fails you, though, you can always just say that you sat down and thought about it really hard and it came to you.
Step 6: Sell the books by preying on natural human drives
We'll use two emotions here that are often called 'negative,' but as we'll see, thinking of these as negative emotions is nonsense! They're positively wonderful for helping you to get people to believe what you want them to believe.
The first is fear. In your book somewhere, you have to say that people who don't believe this book will have bad things happen to them. This is a must. It doesn't matter what the bad thing is, provided it's bad enough.
If you're a traditionalist, burning forever in a lake of fire is good. So is being ground beneath a wheel or being torn apart by demonic dogs. If you're more modern, you can talk about how mysterious spiritual entities will be drawn to unbelievers and clog their thetan energy or something.
People tend to fear death, so playing on that fear is brilliantly successful; you can do it directly, by telling folks that anyone who doesn't believe your book will die; or indirectly, by telling them that they don't really die, but if they don't believe your book they'll come back to life in an undesirable form.
I recommend the latter, because it gives you a natural hook into the other emotion you'll want to use, which is greed. Tell people that they can have things they want and they will be happier if they believe your book. Again, you can do this directly, by saying that people who believe your book will never die but will instead go on to a wondrous place where the streets are made of gold, they will have stables full of hot women who want to fuck them, and they'll be able to create worlds of their own if they like; or do it indirectly, by describing how people who believe your book will become successful and wealthy. (They might not, but that doesn't matter--if you're doing this properly, you will! Should someone tell you "I believed your book and I haven't become rich," you need only say "God is testing you.")
By this time, people will believe your book because they'll be too damn scared not to.
You might think that people would say "Wait a minute--you mean your god prepares pits full of fire and razor-clawed wolves to tear us apart because he has a plan for us and wants us to be happy? How on earth does that make sense?" But you'd be surprised.
Step 7: Lay down the rules
This is trickier than it sounds.
A natural beginner's mistake to make is to set down a bunch of rules for people's lives that will cause them to act the way you want them to. Remember, though, you're dealing with human beings, and human beings are notoriously resistant to changing the way they behave, even when they think that behaving the wrong way will cast them straight into a burning pit full of lava and body thetans.
And also, people are excellent rationalizers, who are very crafty at making up reasons why rules they don't like don't apply to them.
So you have to be careful. You can't just write a bunch of rules without thinking about what the folks yu're talking to are already doing.
Successful religions succeed because they do not try to set morality; they instead cater to the various prejudices, bigotries, and moral beliefs that people already have.
If you live in a slave society, you will not gain any traction if your book says that god thinks slavery is wrong. More likely, you'll get arrested as a public nuisance.
Similarly, if you live in a racist society, you won't gain any followers by telling people that god says blacks and whites are equal. if you live in a society where women are second-class citizens, you're not going to get too far by saying that god wants men to treat women well. You can't just go making new rules willy-nilly; even if you've sold people on all these ideas so far, they're going to balk at actually changing their moral code.
So, the professional instead makes a list of all the various prejudices that the people around him already have, then writes the book to justify those existing prejudices. That way, your book becomes an easier sell.
Don't worry that the prevailing cultural prejudices will change over time. Nobody's actually going to read your entire book anyway; only the parts of it they like. If you write in your book that your god thinks that slavery is a pretty neat idea, and then centuries from now slavery is abolished and people start believing that it's morally wrong or something, they won't say "But wait, this book says that god is OK with slavery! That must mean that god is immoral!" Instead, they'll simply stop reading those parts of your book. It'll be like a little secret, you know?
If you find yourself in a place where you've run out of ideas about what sorts of rules to write about, write about sex. There's always someone doing some sex stuff that his neighbors don't like. You can milk that for thousands of pages, if you want to.
Step 8: Sell the book
If you've written the book correctly, this step is already halfway done. Make sure you feature prominently in the book or (better yet) in the story about the book in some way. Making up stories about your lineage helps.
You don't really have carte blanche to write whatever rues you like into the book, but there's nothing stopping you from putting a few things in there to benefit you. If you sell yourself and sell the rules that benefit you at the same time, you're golden.
It's important to sell yourself in the book because remember, folks will believe that the book was written by your god. If the book makes you out to be special, that will give you legitimacy, and your legitimacy will help you get folks to accept that the book was written by your god. It's win-win!
At this point, you're basically done. It's important not to get too ambitious, though. A good messenger of god knows his limits; if you make a practice of boinking all the townspeople's wives like Joseph Smith did, there's bound to be talk. Similarly, if you try bringing your book and its rules into places that have different prevailing prejudices like Paul did, you may come to a sticky end, which is what usually happens to moral leaders who try to lead rather than follow the morality of their flock.
Instead, I advise stepping away from the day-to-day management of your religion once it becomes established. Let the faithful manage the enterprise; they'll really believe it, so they might even work for free. You can distance yourself from any messes they manage to get into while still collecting generous stipends from your religion. Play your cards right, and by the time you die, you, too, may have a $600,000,000 ranch in California!