Here is one resource for the JW beliefs that are not biblical, and that are serious enough to not be considered Christian beliefs.
Who are the Jehovah’s Witnesses and what are their beliefs?
What do Jehovah’s Witnesses believe? Close scrutiny of their doctrinal position on such subjects as the deity of Christ, salvation, the Trinity, the Holy Spirit, and the atonement shows beyond a doubt that they do not hold to orthodox Christian positions on these subjects. Jehovah’s Witnesses believe Jesus is Michael the archangel, the highest created being. This contradicts many Scriptures which clearly declare Jesus to be God (John 1:1,14, 8:58, 10:30). Jehovah’s Witnesses believe salvation is obtained by a combination of faith, good works, and obedience. This contradicts countless scriptures which declare salvation to be received by grace through faith (John 3:16; Ephesians 2:8-9; Titus 3:5). Jehovah’s Witnesses reject the Trinity, believing Jesus to be a created being and the Holy Spirit to essentially be the inanimate power of God. Jehovah’s Witnesses reject the concept of Christ’s substitutionary atonement and instead hold to a ransom theory, that Jesus’ death was a ransom payment for Adam’s sin.