This article discusses the major benefits to focus groups and how to conduct one. As a new researcher, I have found the insights in the article extremely helpful. A few things that The article not only includes basic information about facilitating a focus group (5-6 open-ended questions, 6-10 of the same demographic, allow 90 minutes, etc...), it also challenges researchers to prepare effectively. For example, it encourages researchers to decide exactly what they want to learn from the group and to take advantage of the focus group's ability to relay product perception.
The article recommends creating an incentive for consumers as well as the use of multiple groups from different demographics to find emerging trends. During the focus group, it recommends creating a comfortable atmosphere, video-taping/recording the group, and repeating back basic answers to ensure that there is a basic understanding.
I believe these are excellent guidelines to qualitative research implementing a focus group. Check out the full article here.