One of the first that I have read is called Becoming a Bold Missionary. This Naturally, I'm pretty timid and quiet. So I thought that any advice about becoming a bold missionary would be welcome.
He uses an analogy that complexly describes me, completely timid and afraid of offence:
"Once on a kind of self-dare, I asked the girl of my dreams to go to the movie with me. I was shocked when she accepted. I walked fearfully to her house and the two of us walked silently to the theater. As we entered I stopped and bought a bag of popcorn. As we watched the movie, I began to eat the popcorn. I knew that I should offer her some, but I was fearful to do so. What would I do if she told me no? I could not stand such rejection. So, out of fear, I ate the whole bag myself."
I highly recommend Becoming a Bold Missionary, especially for those of us who are more timid and nervous about sharing the gospel with strangers. It is a short and quick read, completely worth your time!