My method would involve reading the scriptures with an open mind, allowing the word of God to enlighten you to the truth.
I originally did that when I was but a callow lad and accepted what the scriptures were supposed to be saying. Later in life, I still tried to read with an open mind, but was met with a mass of irreconcilable contradictions.
The clincher for my unbelief, though - as I've mentioned before - was the total absence of any sense of a caring God in my lowest moments, when a sense of such a presence might have made a considerable difference.