Start with a vision of your play. Read your play several times; visualize the scenes; hear the lines; see the interactions between your characters. Use your understanding to create a mental image of what you would like to see in each character.
Publicize your audition dates. Post notices at theaters, in coffee houses and in other public areas. You can also electronically post on websites specifically oriented to the theater community where you live, and on general community bulletin boards such as craigslist. Include the dates of all call-backs and performances. You should also include a brief description of each character and any special requirements, such as singing range or dance capability.
Have an assistant maintain a sign-in sheet. Allocate about 5 minutes for each actor, of which 2 or 3 minutes will be the actor’s monologue, and the remaining 2 or 3 minutes will allow you the chance to take your notes. Depending upon your environment, you might want to have monologues available for auditioners who do not have prepared monologues.
Pass out information on the company, on your expectations, on the schedule of rehearsals and performances to each auditioner. Collect contact information from each auditioner, resumes, photos — whatever extra information you need to make your decision — and communicate with your cast members.
Review the auditions and decide which actors you would like to see in which roles. Although you will have formed an idea of what you expect each character to look like, be open to new possibilities. Call the actors you wish to see, and have them come to the callback.
Print “sides” — brief scenes from the play — for the actors to read from. Mix and match the actors to evaluate their “look” and their interactions. Ask the actors to make different choices during their readings so you can evaluate their ability to take direction. Make sure they note all calendar conflicts so you can factor that in to your decision.
Evaluate your choices and select your cast. In most cases, you will have many options — people who could fill each role — and you’ll cast to fit your vision. Inform all auditioners whether they have been cast or not.