The only difference between a religion and a cult is the number of members, at least in most cases.
Let's examine how religions work compared to how cults work.
Religions require one to believe in something (god, universal consciousness, aliens) and venerate that imaginary being.
Cults sometimes require its members to acknowledge a deity, or a leader(s).
Religions have a conditioning process by which new recruits are acclimated to the faith. Members are encouraged to perform certain rituals that will guide and direct their lives.
Cults have a conditioning process by which new recruits are acclimated to a belief. They're required to practice certain rituals.
Religions brainwash people by having them hear the same message over and over again, week after week. They encourage attending group meetings, which are usually smaller in size than the regular Sunday meetings for example. Why the smaller groups? I can give you an example. One of the local churches in my town has a leadership group. They pull people into that group who they think could be potential leaders in the church. They make those people feel special. These people are being groomed for leadership roles. They will sit in seats of power.
Cults brainwash people by doing the same thing; repeating the same message over and over. Cults have smaller groups within them where people are groomed to be leaders. These people are picked because of their intellect, devotion, and ability to influence others. No different than what religions do.
Religions guilt people into staying a member. If you don't act this way then you're a sinner. If you don't give tithes then you're not doing god's will. If you don't attend church you aren't worshiping god in the right way. If you don't believe, you're condemned by god. Surely, you don't want god as your enemy, right?
Cults guilt people into staying by telling them that if they don't follow the directives of the organization then they must not care for their families or anyone for that matter. I was in an Amway group that used this technique quite often. If you didn't show the "plan" as they called it, then you didn't care about your family or your future.
Religions require its members to have blind faith in a god, and often the leaders of the organization. Don't question authority, just do.
Cults demand its members have blind faith in a deity or a leader(s).
The reason we differentiate cults from religions is that religion is accepted by the mainstream public. Surely, millions of people couldn't be delusional. They sit and pray to an imaginary being, give 10% of their money to god (really, god needs money?), attend weekly services, and proselytize. Cults are more subtle, because they go outside the mainstream. Cult leaders know they won't be accepted by the mainstream, because their beliefs are sometimes extreme compared to mainstream religion.