I'm going to reveal something to you Theists that might allow you to bring down Atheism forever. Why would I want to do such a thing? I'll explain at the end of the post.
OK, so you're a Christian (or some other variety of theist) and you want atheists to see the world the right way (your way). How to go about it?
First, take any and all arguments that you have for your position, and give them an honest evaluation. Break your argument down into a syllogism and evaluate each premise for its truth and then make sure the conclusion follows. Doubt your argument in every way imaginable. Be imaginative in your doubts. Make a list of doubts. And then make a point to figure out how you could respond to those doubts. If you come across a serious hole in your argument, then you should probably not use that argument. More than likely an atheist will be able to find that hole, and he won't be convinced, and then you've wasted your time. On the other hand, if you have seriously examined your argument, looked for possible objections, and come up with some ways to respond to those objections, you will appear very considerate and intelligent to your opponent in a real life debate.
Second, take some time to understand where atheists are coming from. Read a few atheist blogs. Read a few atheist books. Here are some good ones that share reasons for de-conversion:
Why I Believed: Reflections of a Former Missionary
Why I Became an Atheist: A Former Preacher Rejects Christianity
Godless: How an Evangelical Preacher Became One of America's Leading Atheists
And of course atheists and other secular folk have written books responding to pretty much every argument made for the existence of God. A good general survey can be found in John Mackie's The Miracle of Theism as well as Irreligion: A Mathematician Explains Why the Arguments for God Just Don't Add Up. And of course there are plenty of books that are specialized to take up arguments that aren't addressed in such general surveys; For example, arguments for the resurrection of Jesus have been addressed in such works as UFOs, Ghosts, and a Rising God: Debunking the Resurrection of Jesus and The Empty Tomb: Jesus Beyond The Grave and Doubting Jesus' Resurrection: What Happened in the Black Box?
Third, be honest and fair-minded. If your opponent makes a good point which you can't answer, simply say so and tell them you will think about their point (and of course follow up on that promise). When you do that it reflects much better than grasping at straws to save your position.
Fourth, I would suggest listening to debates found online and of course reading apologetic material. But a word of caution: Do NOT assume that anything and everything you hear from a Christian apologist is true. You need to research what they say for yourself so that you will know whether it is true. Some christian apologists make atrocious mistakes in their reasoning and in their fact-checking (that is, if they even bother with it, another reason you need to check behind them) and reading enough atheist material ought to prove this to you. And some Christian apologists (though not all) are blatantly dishonest, as evidenced by my catching Ray Comfort plagiarizing:
Anyway, back on track. What apologetic material would I recommend? I'd say you should start off with Lee Strobel's books, such as The Case for a Creator and The Case for the Real Jesus. Also, make a point to listen to debates online, or to download the debates as mp3 audio and listen to them wherever. If you listen to one or two debates a week, you can vastly increase your knowledge over the course of the next year. And later you can move up to somewhat more sophisticated apologetics, such as Letters to Doubting Thomas: A Case for the Existence of God, and later to the most scholarly, such as The Blackwell Companion to Natural Theology. Again, as a word of caution, I do have major issues with all of these works. Nonetheless, these are the best that the other side has to offer, and so I would recommend them.
That's all the tips I think of for now, though I may write a sequel to this in the future.
As promised, I will reveal the reason I wrote this post. I wrote this post because most Christians that run into (online or off) simply don't know what they ought to know to intelligently defend what they believe. And not knowing enough just wastes everyone's time. When I argue with Christians I often find that they have never bothered to seriously question the stuff they're trying to make me believe. And so they don't make any headway with me. In fact, every time this happens I just become more dismissive of them. Maybe if one of them actually tried he could address the reasons I have for dismissing the Christian religion. And who wouldn't be grateful for such a revelation of the truth? On the other hand, maybe if he looked hard enough at his own faith he would realize that a solid grounding for the Christian faith simply doesn't exist. And then that Christian wouldn't be bothering me anymore, because he would no longer be one.