I agree completely with what Cynthia wrote and  I add one more:

If the group claims to offer a simple experience, but then says you have to go through a process to "be ready" to have it, it's a cult and the "experience" is just the bait to get you to put up with the indoctrination.

This is in contrast to other groups who are not cults, who require a course of intellectual study to prepare you for initiation into the "religion" or whatever it is.