Many things are required when you put on a play. Three things that are important aside from having a good director and cast are the things backstage. Backstage or non-acting aspects include props, sets, and costumes. Each of the three are things we expect to see at any performance big or small.
The worst of things to forget is props. Even more horrible is when an items is supplied but not used. Generally this occurs due to lack of use during rehearsals. This gives all the more reason for backstage help to not procrastinate. The props should be of a high quality. This lends to the level of belief viewers can have. Also try and be accurate for the play. If it is a Greek play don't use flashlights. Unfortunately the details aren't always obvious so I suggest researching the time in which the production is set, not only for use but the get a feeling for what is going on. All of this can also be used for other things, including sets.
Sets are where artists get to do their thing. For this all big furniture goes under the category of props unless it is structural. Sets deign the mood of the play. A dreary cloudy background will mute the play and seem ominous while a sunny day will cheer it all up. A background should extend from where the stage, props, and actors stop, adding depth. Large structural pieces need an experienced builder or a good pattern. Although these sets will not be getting as much intimate use as costumes actors will be walking, climbing, and generally abusing them through practices and performances.
Costuming its the only section where experience is required. A knowledge of sizing, measuring, and sewing is a requisite. In a small production costumes can be borrowed and bought second hand. Often, in a high school, students are responsible for their costume. Old magazines of books on the subject, depending on how far back the plays are set, are invaluable. A color theme is a good way to make sure outfits don't clash. Zippers are a classic mistake in Fairy Tales. I don't mind zippers as longs as they are covered up with a flap of fabric or laces. The last important thing is stage make-up. Detail is lost with distance so features need to be exaggerated. Without make-up people appear washed out under a stage light.
These nuggets of information are a small overview of backstage work. There are other books and things but the best way to learn more is to be in a play.
