Scheduling is your job
On big-budget pictures, scheduling is the job of the 1st AD. Around hereparts, it's the job of the director. Or, you. Yes, it's your job. Whoever you are.
I can't fathom how you're even directing if you don't have the schedule under control. Otherwise the 1st AD is the director and you're the guy with the baseball cap and the cup of coffee in your hand (which honestly, is the way most big-budget pictures are made).
Lock the script
You need a locked script before you can do anything. In the big-budget world a locked script means that the pages themselves are locked, in addition to the scene numbers. What was page 53 when the script was locked is page 53 through the end of post-production (and you end up with "page 53A" and such in order to insert pages.)
Our concern with locking a script is all about the scene numbers and who's in the scene. "Scene 10" should remain "scene 10" from the minute you lock the script 'till the movie gets delivered.
So what happens if you find you desperately need a scene in-between scenes 10 and 11? Well, there are a couple solutions and they both have potential problems. Normally what we do is create a scene "10.5" to go in-between scenes. The potential problem there is that numbering system might interfere with the way we number our shots in CG.
The other way is to create scene "10A". This can be trouble too. On a normal movie set "10A" would be scene 10 camera angle "A". The next setup you do is "10B" and so on. We don't use that system so creating a "10A" shouldn't hurt us unless some computer decides that alphabetically "10A" should go before "10".
But the most important thing is to try to not do any of that once you've locked the script.
And don't change the characters who are in a particular scene once you've locked the script! Now I realize that on some occasions it might be appropriate to change the characters in a scene. But this is a VERY BIG DEAL. Don't do it without making sure that everybody in production is (literally) on the same page as you.
Why is all of this important? You'll see in a moment.
Set up the spreadsheet.
Here's a link to the spreadsheet for the movie 1101. We actually set up our "strip boards" with a flipped x/y axis from the way most movies do it. In other words the actors/characters are on the left column and the scenes are in the remaining columns. But we don't do it that way. That's entirely a result of the way Google Documents allows you to protect the top row and not the left-most row. But otherwise we set up our schedule by-and-large the classic way to do it.
Put every scene in the movie (from scene 1 to scene whatever) on a single sheet of the spreadsheet.
Scene number, whether the scene is an exterior or an interior, where the scene takes place (bedroom, welding shop, deserted wasteland), a brief description of the scene (fight scene, Bob reveals his mother is a ghost, aliens kill the bartender) and then who is in the scene.
Note that each character gets a "number". Typically "1" is the character with the most scenes/lines, "2" is the character with the second-most scenes/lines, etc.
Now, if someone were to go and change scene numbers on you after you've done this, you'd want to strangle them. This is why we lock scripts and don't change scene numbers — it's a strategy to avoid casualties.
Note too that you don't want to change who is in a scene once you've locked either — that could also screw you up badly and make it such that you either call someone you don't need on a day when their character has been cut from the scenes you're shooting (I did that once and felt really bad about it) or, worse, you don't call someone who is critical to shooting a scene you have schedule (yep, did that too, we had to shoot around it.)
Divide the schedule up into "days".
Note that we don't bother putting page counts in our schedules anymore. We used to. We've since given up. Page counts are only semi-useful. If you have big action scenes, the page counts can be really small and yet you have to take many hours to shoot. If you're doing big dialog scenes you can possibly unload 12 to 20 pages before lunch. Everybody knows this. Everybody keeps thinking they can do a schedule based on page counts. Right. Exactly.
Now, the "days" can get very arbitrary. Basically what you're trying to do is balance what actors you have on set (you're trying to avoid calling someone in for a whole day to do half a scene) with where, exactly, the sets are.
This process can be a tad arbitrary. Basically what goes on here is that I make my best guess about what sets we'll have available when. Here I've guessed that "Corridor B" and the Corridor B Airlock, the Facility Interlock, and the Transition Room will all be part of the same set somehow.
It can also be helpful to know the schedule of your actors. Of course, sometimes the schedule you set up determines who can act in the movie because it either works with their schedules or it doesn't. But if you have an actor who you know is only available for one day, then you'll have to make sure all the sets they're on are available on that one day.
As a rule, exteriors should be put together on the same day. Typically exteriors are put at the beginning of the shoot and "cover sets" are scheduled in case of rain. We don't do that. We will either suffer through rain or we'll reschedule (or actually move what was an exterior to an interior if possible).
You want to avoid company moves. You want to keep everyone together on one set for the entire day. That's not always possible. But you'll try to keep all the exteriors within simple walking distance of one another. And if you have to use more than one set, try to make one of the sets a pre-existing set at the location you're building sets at so that you can walk from one to another.
Actually put those days on a calendar.
OK, so you have a spreadsheet where you've dutifully copied all of the scenes onto separate pages called "days". Now you have to turn those days into dates.
All kinds of things can mess you up. Actors' schedules, build-times for sets, whether you can get into a particular location or not, etc.
You'll find a couple different problems with actors. First of all, they're trained to lie. You'll tell them the dates you're shooting and they'll say "Yes, absolutely, I can do that." Then later on they'll say "You know I have to be back at my day-job by 5pm on that day, right?"
The other issue with actors is that they come in two types: those who have 9-5 day jobs so they can act on weekends and at night, and those who work at night and on weekends so they can audition during the day. Not surprisingly, your actors will feel the need to continue to pay rent during your shoot, and will insist on not getting fired from their job just so they can be in a movie.
So you get to juggle all of your actors' schedules, and all of your locations, and all of your sets, just to make the schedule work once.
And then disaster will strike.
Get over it. You're going to get rained out. An actor will get food-poisoning. There will be an emergency. Hopefully nothing serious will happen but the schedule will need to be changed.
Here is an example of a schedule which got bonked because of art department and actor schedules. You'll notice that more than one "day" is scheduled on many of the calendar days. This is the result of some days getting doubled-up due to those above-mentioned conflicts. Are these days hard to shoot? You betcha. Did we do it anyway? Yup.
The project number this calendar is for is "1101". When you just see someone's name, or a name and "NG" that means either we have a meeting with them or they're "no good" on that day. The days with "1101" followed by the name of a "day" are the scheduled days.
For those of you who have worked on what we might call "real" movies, we don't do "day out of day" schedules. I've never seen the point to them. Yeah, some departments find it a bit easier to deal with a "day out of day" schedule but we don't. And you can always go to the original schedule to figure out what scenes are scheduled on what day.
Note that because our pages aren't locked, we're able to go in and make changes to the dialog. Betterizing the dialog is always a good thing. Usually the betterization of dialog is the result of simply cutting dialog. But other times someone will come along and actually re-write a scene. Usually that person will be responsible for otherwise communicating the changes they've made to the other people who are acting in the scene.
Now let's see what happens when we go into actual production.