Determine the assets that are readily available to you. The more things and services you can get for free or at low cost will make producing the show that much easier.
Pick the right musical for your area and your audience. The worst thing you can do is pick a musical that doesn't generate any interest. Remember to keep your audience in mind.
Find the company that owns the rights to the musical if it isn't an original piece. Secure the rights for the time your show is to run. Musicals101.com has a list of companies that own the rights to most musicals that have been produced in North America and Europe.
Plan a realistic budget based on what you think you can beg, borrow and raise. Keep in mind the budget includes everything up to and including the opening night party.
Establish a talented and dedicated production team. If you have a university in your area with a good theater program this would be a good place to look. The musical will sink or swim based on the people you hire.
Start planning various ways to raise money to produce the show. The more money you raise at this stage the less you have to worry about ticket sales covering your expenses.
Publicize the production in as many avenues as you can. Cover all media and the internet as well.
Cast the production with the best talent you can find. Once again, local universities are a good source of talent. If you can afford it, cast someone with name recognition in a lead role to help draw an audience to your show.
Rehearse the show for six to eight weeks. If your cast has many amateur actors this will give them enough time to be prepared to perform in front of an audience.
Plan an opening night party for the cast and crew and a select number of VIP that should include those who donated money or in-kind gifts to the production.