CILT regularly produces tip sheets, guides and collections of external articles. Here are a couple of resources you might find useful.
How can Socratic questions be incorporated into your FLO site? – tip sheet
This CILT-produced tip sheet explores different kinds of Socratic questions you can use for exams, quizzes and learning activities.
Fostering online discussion in higher education
This website has a wealth of ideas for fostering asynchronous online discussion. It includes strategies for engaging students in online forums and is targeted at tertiary educators striving to promote the kinds of discussion that enhance student learning outcomes and experiences.