I wrote earlier that the right tool for the audience to which I was a sometime minister was that the Apostles were willing to die for their faith, and that they were, as far as we know, intelligent men who would not accept martyrdom for what they knew was a lie.
But along with what works, it's probably good to recount what didn't work. The list is longer.
- Jesus is my best friend - this, mentioned to an unbeliever in almost any form, will usually bring back a smart-alecky comeback about invisible friends
- God loves you - a lot of people look at the trouble in the world, now and historically, and say, "that's not believable." It immediately sets up a block which can be overcome, but takes time - which your listener may not grant you
- You don't have much time - this may have worked for Billy Graham, but many people are well-read enough to know that end-time predictions have been going on for over a hundred years in the US. They don't feel a sense of urgency
- If you're not a Christian, you're going to hell - most people who believe in Heaven don't believe this...they believe that pretty much everyone is going to Heaven, with a few exceptions, like Hitler. Additionally, many people have friends of different faiths, and when you try to tell them that their Buddhist buddy is going to Hell, you put your listener in the position where he feels he has to defend his friend. You won't win that fight.
- The Bible says so, and the Bible is right - most of the people you talk with don't believe that the Bible is inerrant.
Because fight against it they will. Sometimes, to the death.