Why you're unsuccessful.
Example #1
You are Japanese. You go over to see your enemy who lives in France. You start speaking to him in Japanese and he responds to you in French. You keep talking, sure that the more you talk, the more he'll listen. He does the same. Eventually it turns to yelling. The only thing is, you don't speak French and he doesn't speak Japanese, you could yell at each other till the sun ceases to shine and you'll never understand what the other is saying.
Example #2
You're a baseball player trying to convince the football team onto success. Telling a football team to win by making sliding into second means nothing to them. As well, when they tell you that their quarterback is injured you just shrug as say "Oh well. He wasn't helping us with hits anyway."
My point: The reason for so fighting amongst theists and atheists is that you're speaking different languages. Theists are shouting in Japanese and atheists in French. Neither side can believe that the other isn't listening and wonder how they can be so dense.
The problem: You're playing with different rulebooks. Theists have a baseball rule book and cannot understand why everyone is running around with a football, and vice versa.
The solution: Learn the other person's language. Running around saying "God exists because the Bible says so" or "God doesn't exist because I don't see Him" is saying "Score a touchdown while on third base" or "Your quarterback injured himself with the baseball bat." The only way to show God to an unbeliever is to do so through the unbeliever's language. Thus Bible is not adequate proof. Just as well, showing that God doesn't exist because you don't believe in the Bible doesn't prove anything as well. The only way to show God does exist to a non-believer is to argue logically without the Bible. The only way to show a believer that God doesn't exist is to argue logically within the Bible. Both can be done.