How to believe “impossible things� – Practice, practice, practice
The process is best started in childhood; the earlier the better. Practice believing that monsters live under the bed, that invisible friends are real, that the tooth fairy leaves money and Santa leaves presents.“‘There’s no use trying,’ [Alice] said: ’one can’t believe impossible things.’ 
�’I daresay you haven’t had much practice,’ said the Queen. ’When I was your age, I always did it for half-an-hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.’� — Lewis Carroll, “Through the Looking Glass.�
Then graduate to believing that donkeys and serpents can speak human language, that people can live for three days inside a fish (or whale) and emerge preaching, that the Earth can stop rotating (‘sun stood still’), a haircut can reduce strength, the Earth can flood ‘to the tops of mountains’, people lived hundreds of years, etc. Steadfastly maintain that all those things are possible (assume a supernatural influence / invisible friend). There is no need to continue claiming that the Sun revolves around the Earth – that battle was lost a couple centuries ago.
Reinforce beliefs with weekly meetings and occasional ‘revivals’, ‘retreats’ or ‘camps’. Encourage frequent personal ‘devotional’ time and reading of approved tales (particularly the ‘good parts’). Discourage critical / analytical thinking (or ‘too much education’), and asking of difficult questions. Concentrate on promises of rewards for belief and punishment for disbelief (both supposedly collectible after you die).
Use social pressure to gain conformity. Demonize non-believers to insulate believers from alternative thinking that might expose flaws in the party line. Emphasize ‘us vs. them’ attitudes. Exile non-believers from the believing community (including their family and former friends).
Glorify believing on ‘faith’ in the absence of verifiable supporting evidence. Attack sources of contradictory information. Discredit and demean competing gods and religions – repeat “My god is bigger and better than your god: or “My god is real and yours is fake.�