If and when you do have to ask a yes or no question, the best technique is to frame the question in such a way that there is a "give-give" taking place, and you are willing to make an up-front commitment on specific parameters, such as limiting the amount of time necessary for the initial meeting. Then end your request with "Is that fair enough?" or simply "Fair enough?" Why does it work? Because everyone wants to be fair, and you are appealing to their sense of fair play. Frame it properly and they will have difficulty refusing your request.