GMCRF or JESUS. One can keep this very simple, and all points are not always needed depending on the background of the individual. The expansion below is to support the theory of these points, not as something necessary to indoctrinate people with. Romans Road, for e.g. can give sufficient verses to bring people to decision at Rom. 10:9-10 (cf. Jn. 3:16).
GOD: Believing in God is not enough because most North Americans believe in God but are not regenerate. Satan also believes in God (James 2), trembles, but is not saved. With some many false gods around, people need to understand basics about the one true God (greater understanding comes after we are saved). There is a difference between YHWH and Allah, for e.g. Some understand God's love, while others do not understand His holiness (character, attributes). In light of the rise of the new atheism, we cannot even assume people are not atheists. No use talking about sin and Savior if they do not even believe in a personal God of any kind. Heb. 11:6; Gen. 1:1
MAN: We contrast the perfection of God with the sinfulness of man. Too many have a new age concept of man or a humanistic version of the supposed goodness of man. The law/Word and the Spirit bring conviction that man is a sinner by choice, relationally separated from the holiness of God. Man cannot save himself or add anything to Christ's work. Man does have free will to receive or reject Christ. Rom. 3:23; Rom. 6:23; Rom. 10:9-10; Jn. 3:16 vs Jn. 3:36
CHRIST: In light of pseudo-cults like JWs and Mormons (Knight's outline is good, but could also be used by Mormons to get people into their cult since they use our semantics), people need to know that Jesus is God Almighty in the flesh (Jn. 1; Phil. 2), not a mere man, created angel, one of many gods, etc. Trusting a counterfeit Christ or false Messiah is worthless (2 Cor. 11:4). He is the Lamb of God (Jn. 1:29), King of kings, Lord of lords, mighty risen Savior (I Cor. 15 Paul makes affirmation of His bodily resurrection core to the gospel). So, Jesus is God, Lord, Savior, risen from the dead. He alone can bridge the gap between God and man and reconcile us to Him.
Repentant-Faith/Repentance Faith: We are willing to turn from sin, false gods, Self to Jesus as God alone. We receive the person and work of Christ, His grace, by faith (we cease the rebellion and denial of God's right to rule our lives). Works, self-righteousness, x,y,z are not necessary. Saving faith will be persisted in, not renounced (apostasy, falling away is possible vs OSAS, but He is able to keep us from falling Jude 24-25; I Jn. 5:11-13). Eph. 2:8-10; Jn. 1:12; Titus 3:5.
How do you get to heaven? Faith in the Lord Jesus/Knowing Jesus (I Cor. 15:1-4; Jn. 17:3), nothing more or less. 'Follow me'. We can add all the negatives as insufficient to get one there: believing in a generic 'God' (Jn. 14:6; Acts 4:12; Jn. 3:16), going to church, cleaning up one's own life to be good, being religious without relationship with God, joining a special sect or cult or religion, doing our best, not hurting anyone, etc.
Once one is saved, it is normative to grow in the grace and knowledge of Christ (character). This growth can be helped/evidenced by spiritual disciplines such as prayer, worship, Bible study/meditation/obedience, church fellowship, discipleship-evangelism, etc.
How to preach the gospel (Finney quote):