So much of it has to do with your ability, not just as a dentist, but as a person in general to feel comfortable communicating with people in general. If you're able to do that, then adding in the dental component is an easy transition.
One of the key things that I do, is assess what level of technical detail you need to communicate to patients in. For example, how you're going to explain what you're doing while restoring #30 occlussal to a 7 year old will be different than to a 37 yr old, but in the end you should be able to have both of those ages understand the concept of what and why you're doing what you are to that tooth.
Personally I like to try and use humor often when discussing things with patients. Most of the time, our patients have some degree of anxiety while in our chairs, and trying to get them to relax and take their mind off what they think will happen (pain often) while in our chairs I have found to help out a great deal. Not really sure if there's a book that I have come across that deals with this as much as it's just been some trial and error on my part over the years as well as listening to numerous colleagues and continuing education speakers talk about patient communication and management and then applying that in my own operatories to see what works for me