You asked in another post 2 questions - 'gimme proofs for God' (consider this awnswered - see posts above) and then 'once you gimme proofs for God tell me how it's the God of Christianity.' This is where we get to this.
The next thing, then, after being convinced of theism, is the reliability of the New Testament as a historical account, including the Gospels. Written by eyewitnesses, or people who knew and were writing down accounts for eyewitnesses relatively (for ancient history) soon after they happened (indeed relative to sources for other bits of ancient history the Gospel's being written down between 30-50 years after the fact is actually incomparable to other historical sources which are normally from a much longer timeframe after the event their describing). Then you have the book of Acts and the epistles. 1 Corinthians 15 I think it is has what has been recognised as an early Christian creed with the essentials of the faith, estimated to have been developed and affirmed within the first few months to few years of Christ's death. Christ claimed he was and was crucified for claiming to be God, something no other prophet dared do. He and fulfulled numerous prophecies of the OT which you can read up about. We have more copies of ancient manuscripts for NT than for any other ancient text and they all align with each other pretty much perfectly and, where they don't it is in the minutest of details as to render the differences completely insignificant resulting in unchanged and firmly affirmed doctrine.
Coming round to understanding the reliability of the NT is the second tier of the approach. The third is that, now you have that in the bag, you need to be convinced of Jesus being ressurected.
Pretty much all scholars, secular or otherwise, affirm that at the very least, the following as comprising the minimal historical facts: that Jesus was a real historical person, had a bunch of followers, was crucified, his tomb was found empty three days later, and his followers claimed to see him and/or had experiences of interacting with him following his crucifxion in his new glorified body. Note they don't say he was actually ressurected, only that his followers claimed to see him or were convinced they saw him alive after his death.
Cool, so now we got those basics down, we just have to eliminate the possiblities of why the tomb was found empty, given it is by concensus considered historical fact. *Goes and does research* Hmm, would seem that any of the alternative theories to explain the tomb being empty that don't involve him being ressurected by God are, in light of my new found belief in an immiment God who would be perfectly capable of performing a miracle like raising someone from the dead, surprisingly thin. Therefore he was ressurected as the Son of God in a glorified body by the father in the process defeating death and making good on his promise for eternal life. See also the evidence for the shroud, which according to all indications is simply miraculous.
Cool, welcome to Christianity.
And this came up a couple of times but I don't think it was emphasised enough - we use the fact that the apostles died violent deaths for dying what they believed in which add's to Christianity's credibility. You say, 'sure but there are martyrs for lots of types of beliefs, just because people die for it doesn't make it true.' But the difference between the apostles and all other martyrs is that they were dying for something, a person, the risen Christ, they claimed to have seen with their own eyes and spoke to and touched and interacted with. Other martyrs were just dying for what someone or something else had told them, (like the fact that Christ is risen, which is admirable but not extraordinary) and not for experiencing the thing themselves. This adds great weight to the claims of the NT in the Christian's mind.