There are four or five key areas of planning in preparation for an Open Space meeting. Sometimes the first and third items listed here get rolled into the invitation process, sometimes the input of a leadership group is so important that it is addressed as a distinct piece of work. That said, here is the short list of preparation issues to consider...
The Invitation is simply the central question to be addressed, accompanied by the cleanest possible story of (1) what is happening, (2) how we got here, (3) what is needed (to make or do or discuss) now, (4) when and where we will gather (to make or do or discuss it). This might be as short as four sentences, or as long as four pages. What is important is that when people on the Invitation List read it, they hear the history, happenings, and needs as their own. This is how they know that they belong in the gathering when it happens. The key to writing the invitation is to speak the truth and ask, very carefully, for what is most important at this moment in the history of the group or organization. Good invitations often mix and balance grandness and achievability, passion and practicality.
The Invitation List should include everyone, yes everyone, who might have a stake or interest or contribution to make to the purpose. Anyone willing to show up, learn and contribute to the work can be welcomed.
Special Inputs and Decisions from a leadership group can point out for invitees (1) latest data on conditions, needs and expectations, (2) strategic directions and priorities, (3) assets and resources already available for consideration or application, and/or (4) acknowledged boundaries, obstacles or otherwise non-negotiable parameters within which work must somehow progress.
Program Logistics includes the place, the amount of time, the materials and even food plans. All of these things need to be scoped, scaled and sourced in alignment with the purpose stated in the invitation and the group to be gathered.
Sustainability and follow-through depend primarily on the support provided. No support, no sustained spirit -- and probably no "action." Some important supports include documentation, next meeting dates, funding or other resources, and sometimes facilitation support for future meetings.