In my own experience, when I become overly focused on the mechanics of moderating (i.e., following techniques by the book, etc.), my moderating has suffered. Going into various techniques (e.g., laddering) can help in getting questions answered or getting better answers. A skilled moderator will know when to go down that path and when not to. It takes experience. It takes making mistakes to know when to do it and when not to. It takes research and knowledge in the field/market that the moderator may not have.
Nevertheless, one must not lose sight of the basics. Respondents know when a question is genuine. They know when a smile is forced or not, and their willingness to answer and engage in the discussing is directly influenced as a result. It is better to form a relationship (albeit, a temporary one) that is genuine. Rapport will go a long way.
Find things to like about each respondent. Give respondents a reason to talk to each other. Show why the topic being discussed is relevant and even interesting. All of these aspects are established in the introduction of the group, although often moderators will only have 5 minutes allotted for the task. Take the time (or more if needed) and use it to get the respondents smiling and relaxed. It makes the group much easier to conduct and more rewarding for the clients and respondents alike.