Everything now is so certain. They are offered free gifts, meals, or a free 'no obligation' lecture. Some sects have perfected the use of subliminal messages, conveyed through key words which are stressed in ordinary conversation. Then the group will reinforce motivation by making the novice behave in a certain way. Sometimes disorientation due to lack of sleep, a heavy work schedule, deprivation of certain vitamins etc.
Privacy is taken away, and loyalty demanded.
But eventually most will drop out. The leader has feet of clay. The group promises more than it delivers. Don't send money or hand over original documents, and don't give up trying to get your children back. If the cult is associated with the occult, and has seances, etc.