Plan, Meet, Write-Up

In principle, the three fundamental steps that make a meeting great are to (1) plan what you are going to meet about, (2) actually meet according to the plan, and then (3) write up the meeting results.
Practical tip: In the case of an upcoming meeting, the meeting facilitator and/or group leaders should huddle in advance to be clear on the meeting objectives, agenda, roles, how it will be recorded, and logistics such as invitations, space, food, nametags, etc. Talk it through and plan out how each part of the meeting will work. Advance planning increases chances that you will have on hand the things you need for the meeting to go well and sharing the plan in advance increases chances that participants will come prepared and that their expectations will be on target.
Then, run the meeting according to plan (although always be prepared to be flexible and responsive to things unplanned). Meeting according to plan provides security for participants.
After, provide participants with a write-up that is more than a simple chronological transcript. Organize the thoughts and stories shared, name the themes discussed, and format the writeup so it is pleasant to read and easy to refer to later. In the writeup you can provide a logical organizational structure even if things seemed quite confusing during the actual meeting.
Do not skimp on the pre-planning or the post-write-up. These are the two things that often distinguish a great meeting from a mediocre one.