I’ve just posted an example preshow checklist in the Presets topic of Uploaded Forms. If you have any books on SM, they are also good sources of examples of preshow duties. As others have mentioned, your routine will be based on the needs of the specific show and theater. My philosophy is that anything that can be done before the show, and checked off, should be; it just leaves less room for error. Conducting a blackout check to confirming worklights are off, running lights are on, and show lights are then set to the proper cue, is one of the most basic preshow functions, as is checking that crew and cast are at the theater. I like to note the little things I need to call the show comfortably, such as water and pencils and tissues. Connecting with the House Manager before the show, if you have one, is another task that’s easy to overlook. It may be helpful for you to work backwards by putting yourself in the first cue of the show and looking at everything that need to be in place for that to happen smoothly. I often keep a half-complete preshow list beside me in tech so I can add things to it as I see a need develop.
If I have a competent and trustworthy ASM, I often only double-check on stage presets that need to be there before House Open, and do a visual check on major items offstage. I may also have it on my list to ask/remind the ASM to check a certain preset, and I always ask them if their own preshow checklist is complete before I open the house. If you don’t have a crew or ASM on deck, your preset list is basically the first page of your run sheet.
I use sheet protectors and a wet-erase marker for my preshow checklist. Dramachick, the bound sheet protector sounds really useful!