Identify the type of dinner theatre operation you want to organize because you need to know this before you can proceed with your planning. Determine where you want to locate your dinner theatre, or, for a traveling dinner theatre troupe where you want to locate the headquarters of your dinner theatre.
Determine how much funding you will need to open a mystery dinner theatre, and how you will obtain that funding. Funding needs will vary with your location, the resources available to you in your area and the scope of mystery dinner theatre you plan to organize. Plan to allow in your budget for a facility such as a restaurant suited to dinner theatre, travel costs for a troupe that provides on-location dinner theatre. Include, also, salaries for actors, a chef, additional kitchen help and servers. Factor in costs of any licenses and permits will need. Plan for advertising and promotional costs and plan to invest a significant amount in advertising at the outset of your dinner theatre.
Determine what sort of licensing and other permits a dinner theatre requires in the area that you will locate your dinner theatre. Apply for such permits as early in the process as possible. Plan to attend community meetings in a town or appear before a city councilor's meeting in a city at which neighbors will have an opportunity to voice any objections they have to the opening of such an operation.
Determine, once you have established a baseline budget, if you can trim some of your costs while also benefiting your dinner theatre. Put together, for example, a core group of actors blended with novice actors recruited through local college theatre groups. Use less experienced actors to help save costs (they will have lower hourly rates than more experienced actors) and to benefit your program as they learn their craft from the more experienced actors. Consider doing the same thing with the kitchen help by employing a blend of experienced chefs and apprentice kitchen workers.
Arrange --- once you have funding and appropriate approvals, licenses and permits in place --- to lease or purchase the necessary facilities for the type of dinner theatre you plan to operate. Determine, once you have ensured the availability of facilities, on an opening date for your dinner theatre.
Recruit actors for your dinner theatre in sufficient time ahead of your planned opening date: potentially starting while you are still engaging and preparing your facilities. Arrange advertising and promotional efforts focusing around your opening date to draw interest at the outset to your mystery dinner theatre. Engage the actors, especially the more experienced ones, in devising creative ideas for your kickoff promotional efforts; for example, presenting minute mysteries in community locations like schools or museums or including a mystery novelist in the guest list of debut events.