Cults and legitimate Christian Churches

[Kofi]

What are the difference between a cult and a legitimate christian church? There are thousands of cults and dangerous religious groups in North America. In Africa today, church is a family business in which people engage themselves just to gain some financial benefits. In Africa today, a pastor who doesn't perform miracles isn't a good pastor and almost all the new pastors in Africa today are going to the extremes in order to perform miracles. The more miracles you perform in Africa, the larger your congregation. A big cross on the top of a church building doesn't make it a christian church. You may find big crosses and statues of the virgin Mary inside the so-called church buildings but that doesn't make them churches. here is a quotation from the bible:
Watch out for false prophets. They come to you in sheep's clothing, but inwardly they are ferocious wolves. By their fruit you will recognize them. Do people pick grapes from thorn bushes, or figs from thistles? Likewise every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus, by their fruit you will recognize them (Matthew 7:15-20).

My question is, How do we tell the sheep from the goat? How do we tell good christian churches from cults? How do we tell good Pastors from fake Prophets? What do you think?