This wont be the best answer : p But Id listen to people who actually do this everyday.
I often do with Christians who stand for the word against Islam, I really like people like David Wood and Nabeel Qureshi and others, they have a youtube page called Acts 17 Apologetics. Ive really learned alot from them, how to defend Gods word, which verses you need to know to answer questions. I dont have any books I can lead you to : p But I really like what these guys are doing, and I think you could learn a little from them, if you are interested in checking them out : p
Hope that helps.