The main difference between Jehovah's witnesses and Christians is that Christians believe in the Holy Trinity, which means Jesus (the son), the spirit, and God (the father). Jehovah's witnesses, on the other hand, see the Holy Trinity as something that holds people from recognizing the one true God, which is Jehovah.
They also believe that the world is ending. They do not believe in hell, and they also think that their people serve God on earth and that those who fulfill God's purpose are rewarded and they remain on earth, but if they do not, they die. They also believe that a small group of people end up in heaven. Christians believe that when you die, you go to heaven or hell.