The key to being a successful cult leader is putting people in a position where only you can save them.
A role model for you would be Sidious's manipulation of Anakin.
"but not from a Jedi"
In order for the cult to be successful you have to have ideas that are outside the mainstream and as unique as possible so that once they accept the bait, like a fish on a hook, you can reel them in without them thinking they can just join another church.
The more out there the doctrine is the more people assume its true because why would you invent something so crazy?
The next key is, using subtle nods to things people already know but don't have hardly any concrete information about. Combine these elements with each other. For example. You should say aliens exist. But they are angels. And they travel in these flexible spherical bubbles that stretch into a saucer shape depending on how fast its moving. In their minds, they'll be like "oh that makes sense!" And then you tell them that the government knows about them and they've tried to communicate this message straight to our officials for dissemination but the government was hostile because it didn't like the idea of love because they make money on wars and this message would take all that away because this message has no need for governments. The government even captured 2 angels at Area 51 and dissected them.
A whistle blower leaked this to Hollywood around the time they made the movie Independence Day but the government learned about it and made the aliens look scary to scare people into wanting to fight them. In reality when they take someone, they are taking them to heaven. They take people all the time, but some people they have to bring back because it they let them take a test and if they failed they had to go back. And since they had to mind wipe them like Men in Black, they all come back with some stupid story about anal probes.
How do you know all this? Because Kallel, one of the angels, told you and made it your divine mission to disseminate the truth to as many people as you can. Kallel's been to our planet before. He can take human form but one day he saw someone falling from a building and that's how the superman myth got started.
See? The story side of this is easy. You make it more potent by weaving in conspiracy theories.
Now if you want a harem you simply need a story for why you must reproduce at a faster pace. For example, you could say your DNA is what allows you to communicate with the angels. And in order for more humans to communicate with them too and help spread their guidance and direction you obviously need to merge your DNA with others so that the offspring will be able to communicate with the angels. This ability will fully manifest when they turn 30 which is when you had your "First Contact". That's another key thing. You gotta label and brand these events. Reuse buzz words. "God is good? All the time." stuff like that.
By the time your 100 offspring get to the age where you could be proven a liar you'll have had a great life and been taken up to heaven in a cloud (retired to an island paradise). Make sure you give plenty of rules; one of which should be that your concubines (just have 1 wife) must wear all red starting a week before their period. This is called "The Waiting" and the purpose is for you to avoid PMS. And once you give this rule to the rest of your followers you'll get an increase in male followers.
As you can see I am very capable of coaching you, which I will do for only 15% of your profits.
