A technologically advanced (but rather morally stunted) alien species have come across the Earth during the modern age. For whatever reason, they want humanity to worship them. They have no ulterior motives (atleast none that would affect humans), they just want as many people to acknowledge their (self-proclaimed) greatness.
As they don't have any ethical mandates restricting their conduct towards people, intimidation would at first seem like a surefire method to achieve their goal, simply treaten to kill anybody who doesn't bow down to them, right?
Unfortunately this won't work. They don't simply want people to periodically complete some ritual fearing for their lives, they want true belief. In fact they don't care how humans choose to venerate them so long as they genuinely believe them to be god-like and deserving of reverance and obedience.
Another thing to point out, they can't just rig up some holographic emitters and pretend to be Zeus or Jesus or some other human deity. That might make sense if they had some nefarious purpose that needed the compliance of people and assuming the image of some already established god was just a ploy in order to get what they wanted, but since the only thing they want is for humanity to praise them personally, this wouldn't work.
Being technologically advanced they can do rather incredible feats including:
Bio-engineering powerful bio-weapons, artificial pathogens.
Using their extensive knowledge of physics to achieve FTL travel, wormholes.
Easily building fusion reactors and relatively easily building dyson swarms.
Curing essentially any human disease.
Hacking any website/online service with low to medium level security.
So the question of course is, how, using their advanced technology should this alien species establish and grow as quickly as possible their new cult/religion? What opposition will they face?