OK, let's have a go:-

1. Devise a god/goddess who has interesting characteristecs, meaning people will talk about him/her, but no characteristecs AT ALL that can actually be tested.

2. Write a book with back-story for your deity. Make sure there is much talk of 'virtue' (and it being praised and rewarded) and 'sin' (that must be condemned and punished by the deity). Do not, however, carefully define what is virtuous and what is sinful, so that your worshippers can simply 'cut and paste' their own prejudices onto the words and declare then to be the deity's own truth. In addition divide your holy book up into sections, sub-sections and sub-sub-sections, all of which are carefully numbered, so that it can be easily referenced.

3. Claim that your holy book wasn't, in fact, written by you, but was the work of ancient schollars from the dark depths of time - at least 1000 years ago. Write the book in a style that supports this claim - lots of 'whereats', 'begats', etc. You might feel worried that potential worshippers will look into this story and see the falseness of it. Don't worry - if you can get the idiots hooked they won't question anything.

4. Build into your faith a magical 'get out of moral jail free' card - praying for forgiveness is a good one - so your worshippers know that however much they act like complete cunts, they can 'do the thing', get forgiven, and then polish their haloes while pretending to be angels.

5. Set up the source of your religious incone - tithes, etc - after all, there's no point starting a religion unless you're getting rich doing it.

6. Claim yourself to be the true 'manifestation upon earth' of your god/goddess - and build that into your holy book. After all, you don't want any other bugger jumping in and claiming your idea.

7. Dress in a MAGNIFICENT dress (regardless of gender) matched to a RIDICULOUS hat.

I think that does it.

Needs more - how to establish no tax status and avoid all taxes.
Add in a spice of how to bitch about being persecuted.

Gotta think of a good kinky icon the fillers can wear around their necks

Being that I'm a reasonably good creative writer, I would come up with the most outlandish, outrageous, ridiculous foundation I could dream up for my religion. I would use the preposterous foundations of Mormonism and Scientology as my guides, smoke a bunch of weed, do Tequila shots and let my imagination run wild.

I think designing my own religion would be a blast.

I have to start one. As long as I'm God and Ruler Supreme on it, it's absolutely perfect for me... lol!!!

Yea……just be a total dickhead and a lowlife scum.

Wrong question. “How to Start a Religion that Fluorishes” should be your objective. For that you’ll need unfalsifiability, forced conversions, psychological/emotional intimidation and manipulation, demonization of otherness, shaming, rewards and threats in an unverifiable afterlife, repression, censorship, control of information….

L Ron Hubbard did a pretty good job with a phony religion. Actually they are all phony.