There is plenty of historical evidence for the existence and resurrection of Christ. Josh McDowell's book The Resurrection Factor is helpful here. However, the most convincing evidence for the reality of Christ is ultimately the regenerating work of God. No one will believe, regardless of the evidence, unless he is drawn by the Father (John 6; Luke 16:19-31). God opens the heart of the unbeliever (Acts 16:14; Romans 8:28-30; 1 Corinthians 1:9; 1 Peter 2:9). The Holy Spirit also gives assurance to the believer (John 15:26-27; 2 Corinthians 1:20-22, 5:1-5; Ephesians 1:11-14). James White's sermon “Why Am I a Christian?” may be helpful: http://mp3.aomin.org/JRW/WhyAmIAChristian.mp3