I really should have mentioned this before, because it's important:

By now, on the eve of the first day of shooting, you will have a cold.

Actually, I'm not sure whether this is a general thing, because I've never seen it mentioned before. But unless you are super-organised, you'll have been doing a couple of late nights getting everything organised, you'll have been having nightmares about forgetting equipment, or any of the other many things you should have thought of before now, and you'll be feeling that tickling sensation in your throat that is natures way of telling you that you've been working too hard, you're too stressed, and you are now going to pay for your weakened immune system with a cold that will last for the duration of the shoot. Maybe it's just me (I'm quite susceptable to colds, just getting over a three-weeker now). In any case, here's some advice:

As you get closer and closer to the shoot, you'll be more and more stressed. Great time for a cold to strike. I recommend vitamin C and Zinc tablets as a preventative measure. I'm not joking.

Right, that over with, lets talk about what's actually going to happen when you're shooting. The heavy preproduction work is done, you've got log sheets (if you need 'em - heck, if you're doing something really short, I wouldn't get too fussed), or a list of the shots you want to take if you don't do this - and all your equipment.

Now, obviously you'll need a whole bunch of equipment for the shoot. Most of it is obvious stuff like the camera and lighting & sound gear - I've made an list of the stuff that I use here.

But here's some extra stuff you might wish to consider for your shoot.

T-shirts.
Amanda, Chris and I made up OUAT t-shirts to had out to cast and crew. They were a big success - I thought they really drew everyone in together and made them feel more of a team that was actually achieving something. I'm very proud of the t-shirts, and recommend doing something like this highly. We did our own printing - lots of fun!

Catering.
Don't forget to do this! You'll drive your cast and crew mad if they have to pay for their own food, or don't get it on a regular basis. Food actually accounted for most of the cost of the shooting. I took everyone out for lunch and dinner for the four days of shooting - because there were only eight other people, this wasn't so bad. But for larger crews or longer shoots, I really recommend getting a dedicated caterer - parents are a good bet for this one. We currently use Anna's mother, who is very traditionally Greek and delighted to provide food for many thousands of people, should we somehow round this many extras up. Anyway, besides the regular meals, you should provide snacks and caffinated beverages. And probably get an esky to keep them all cold.

Monitor.
Very good idea, this - a small TV will do the trick, something portable but in colour. This is for the director to watch the action of each shot. You should be able to plug the camera into the TV and be able to watch it live while you're shooting the relatively static shots.

Chairs.
Portable folding chairs for the crew and cast when they're not on-camera. Very important. There's no such thing as a short film shoot. Of course, if you're shooting entirely indoors, this isn't so much of a problem. Folding chairs, because you'll need to move the chairs for the crew around the room when you shoot from different angles.

Table/trolley.
You'll need a folding table or some kind of trolley to put the monitor on. If you have separate sound equipment, you'll need something for that, too. These have to be portable because you'll be moving them around between shots. You wouldn't believe how much time this takes - moving the camera, then all the cords, shifting the monitor on its trolley, and then moving all the scripts that people have left lying all over the place, and the tripods, light equipment, tool kits, rolls of gaffer tape, makeup kits, and so on. Nice if the trolley has some containers for this stuff.

Gaffer tape.
Useful for everything. Taping down power cords so the actors don't trip over them. Holding the props in the right positions. Marking the actor's starting positions. And so on. Get some heavy black tape, and also some of that thin white papery tape as well.

Lens cleaning cloth.
You'll use this regularly, as well as those little bottles of compressed air for blowing dust off the lens. I have no idea how the lens gets so dirty so quickly, but you will definitely regret it if you clean the lens with your t-shirt.

Spare camera batteries.
Obvious, but very, very necessary. One thing to note: if you are running solely off batteries, one spare battery isn't enough. Most batteries nowadays take longer to charge than they do to run down, so when you've done one battery change, and are charging up the original battery, it won't be fully charged by the time you need it again. Usually it won't be a problem because you'll be taking rest breaks, but still... run off mains power whenever you can.

Extension and other cords.
If you have lighting equipment, this is fairly obvious. Even if you don't, you'll need to plug in your monitor (if you have one), your camera (even if you have batteries, you'll want to plug in the recharger), and so on. There will be something, and the power plug will be just out of reach. We had three extension cords for OUAT, and used all of them. You'll also probably need cords to connect the camera to the monitor, if you're using one, and the microphones to the sound recorder. You'll want long cords, at least six metres.

Power boards.
Like extension cords, you'll need at least one. We had the monitor, a minidisc recorder, and the camera recharger. Lighting equipment would have required another board, probably a separate one - most power boards have circuit breakers, and the lights draw a lot of current.

Clothing.
Crew should wear black, matte clothing (ie. nothing reflective) if possible. Cast should avoid the colour red if possible, 'cause on most DV cameras, big areas of red look crap. Even the TRV900, the expensive one that we use, it isn't the best.

Makeup
Get some cheap foundation in a variety of shades, a bunch of applicators, and some small mirrors. The actors will need the foundation to look natural, believe it or not - without it, the males will look like they have permanent five-o-clock shadow and everyone will look unnaturally shiny. The foundation (powder or compact, usually, but some liquid foundation may be necessary for zits that pop up between days) is usually needed on the nose and the forehead, the two really shiny bits of the face. This will be especially necessary if you are using lighting, because its heat will make the actors sweat a bit. You probably won't need a separate makeup person if you're running tight - get the actors to apply the makeup to each other.

Mobile phones.
So, how are all the extras going to call you and tell you that they can't make it if they don't have your mobile phone number? Be sure to have a mobile phone, and tell everyone involved in the production the number. Get the numbers of principal crew and cast members as well, assuming they have mobiles. If they don't, then you should really encourage them to borrow a mobile. Even if they are as reliable as anything, you will almost certainly remember something that they should bring before they leave home. Or you need to call everyone and tell them that the location has changed due to Fred's mom not letting you film in her bedroom.

Copies of the script.
You'll want a copy for everyone, of course. I'd hand out the copies on the first day of shooting, because you'll probably be making minor changes to the script right up until the last minute, and you'll want those minor changes on all the scripts you hand out, right?

Clapperboard.
I'm still debating whether these are really necessary nowadays. You're almost certainly using a DV camera, right? And a DV editing suite like FinalCut Pro or Adobe Premiere? Well, a lot of the functions of a clapperboard are superceded to a degree by this stuff. A clapperboard is a helping hand for the editor later, and serves a couple of purposes - the clapping sound/motion provide a simple synchronisation point for separate sound and picture - for example, if you're recording sound separately (as we did for Once Upon A Time). It also shows what shot and take this sequence is of.
However, when you're editing DV, the synchronisation of separate sound and picture tracks is pretty simple - just line up the audio waveforms of the camera's sound with your external device's sound. DON'T FORGET TO RECORD CAMERA SOUND, of course.
And the shot/take number isn't all that useful. For one thing, it's usually pretty obvious which shot you have when you're reviewing the tape later. And it ain't hard to work out which take the shot is of. Anyway, we'll get into this more in post-production, but suffice to say, we used a clapperboard in Once Upon A Time, but I think it slowed us down and wasn't as useful as I'd thought it would be.

Whiteboard/chalkboard.
You got professional actors who memorised all their lines in advance? Wonderful. Bugger off. This web page isn't for you. The rest of us got actors with potential and maybe a little experience, but who have other occupations and other concerns with their lives. They're (hopefully) excited about the film - before you've started, anyway - and are committed enough to show up every day and get their free t-shirt at the end of the shoot (which you have already made up, right?) But don't expect them to have memorised all their lines, especially if you have anything tricky. So: the whiteboard/chalkboard, with appropriate hints, will make things a lot easier for those long monologues. Even seeing the thing out of the corner of your eye can help, believe me.
If you don't want to use a whiteboard, fair enough - prompts from someone in the crew with a copy of the script (usually the director) will help out, as will keeping the shots short. However, at the end of a long day of shooting, when everyone is frazzled and the actors are almost asleep, they will appreciate this one.