Once you have committed to a production, it is important to learn as many details as you can. First off, you should check if you are the “lighting guy,” “programmer” or “LD.” In this industry you can easily be hired as any, or all, of the above. If you and your client do not have a clear understanding early on, this might cause trouble during the production. Some lighting companies often will hire you to handle all aspects of lighting for a show. You will design the plot and run the crew, as well as program and operate the show. On the other hand, many productions will have a full crew and lighting designer and only expect you to program the console. Always be sure to define your role when you book the gig.
-From Brad Schiller's February Feeding the Machines column