I have to say I'm really appreciating what I've read and reread from Jerram Barrs' The Heart of Evangelism. I think it's one of the most important books on evangelism in print. It's both comprehensive and insightful. Here's a great section on asking questions...
We need to learn to ask questions that will help us understand what is in a person's heart and mind. That is what Jesus did with this man (expert in the law in the Good Samaritan story), and we find Him taking this approach repeatedly in His discussions with people. Francis Schaeffer used to say that if he had only one hour with someone, he would spend fifty-five minutes asking questions and five minutes trying to say something that would speak to his or her situation, once he understood a little more about what was going in in his or her heart and mind. What is needed is genuine love and concern for the person we are meeting, a readiness to ask questions because we truly desire to know the person, and prayer for the discernment of the Holy Spirit about what to say.
I'm also starting into Barrs' lectures from the Covenant Seminary class on Apologetics and Outreach. It's available in audio or transcript and includes a study guide as well. Very helpful.