The goals for discussions will vary depending upon where you are in the sequence of your course. Perhaps you are using an author's ideas to generate ideas for students' writing, or pulling main ideas from a text and arranging them into an academic summary. You might want to determine whether or not a writer's choices are effective. You'll want to ask yourself, when planning these discussions, "What features of a text should we focus on in order to meet the daily goal?"
If the goal is to teach students summary skills, your discussion questions should be geared to accommodate this. You might create questions that ask students to define a writer's purpose and locate the main ideas. In most cases though, discussions will be dynamic, taking into account multiple purposes and goals.
Your text, course outline, or syllabus may include discussion questions as starting points. Use these as a guide, but also practice developing your own. If you are teaching students how to write a good essay, write out a list of questions that you think are relevant to an essay. Then look back at the daily goals and select those that best reflect these goals.
Arrange discussion questions in a logical order, but also plan to be flexible. Make a list of things that must be covered. Create a hierarchy of questions, but try not to insist on a particular order (discussions usually do not follow a linear path). Rather, think about how questions connect to one another. This way you can adapt during discussions.
Unfortunately, students won't always provide the insightful responses we dream of. Anticipate where your questions may receive shallow answers and plan to engage students with questions like, "Interesting, can you give a specific example for that? Or, can anyone take what Tony just said a go a bit further with it?"
Also, think about how you might phrase questions differently. Sometimes students are silent because they're not sure of what you're asking. Next to each question, list a few alternative ways to ask it. This may be all it takes to turn a tedious discussion into something exciting.