This Bible Study Guides section of the Zondervan website gives information on entire guide series: names of guides in the series, information on the style of the series, and links to the detail pages of each book. The detail pages (in the Book section on the Zondervan website) contain more specific information from each book including sample text.
First consider a few basics. What are the interests and needs of the group or person that will be doing the study? What are the goals for the study? Keep those ideas in mind as you start searching through the options. After a series piques your interest, look at a specific book in the series. Try reading the sample text from the book.
Does the study encourage communication?
Are the study questions provocative?
Does the study encourage practical discussion of real-life situations instead of simple facts and opinions?
Does the study encourage everyone to participate rather than just a few people who might know more about a particular topic?
Do the leader's notes empower the leader to support discussion?
Does the study consider the needs of the group?
Can people still easily participate if they have little time for personal study?
Is the study flexible?