How to behave on a film or TV set
Whether you are working on a film or TV production for free, or being paid for the privilege, it doesn't change how you should behave on set. To get the most out of your experience, try your best to be enthusiastic, professional, and (most importantly) safe.
If you are lucky enough to be invited onto a film or TV set for some work experience, then you will of course be keen to leave a good impression on your potential employers. Make sure you are enthusiastic and interested in the things going on around you and, when it feels appropriate, ask as many questions as you can think of (you'll be surprised how quickly you think of extra questions on your feet). Even if you are there to impress one person in particular (perhaps the producer, the director or the production manager), try talking to as many different people as possible, asking what their role is and why they enjoy it. The majority of production crew have an immense passion for their job, and will be happy to answer your questions. Asking about their background is a great way of encouraging them to describe what they have done in the past, and how they got to where they are today.
If you are naturally a chatty person, that is great, but be careful not to talk too much or ask questions at awkward moments (for example, just after you're heard someone shout 'Quiet on Set!', or 'Action!'). Remember, it might be your first time on a film or TV set, but everyone else has a job to do, and so they won't have a lot of time to talk to you. If you are shadowing someone in particular, stick close to them and follow their lead, but don't be disappointed if they don't have as much time for you as you had expected. You probably won't be doing anything wrong; they simply have to concentrate on their job.
You must also try to be as professional as those around you. We've all been on set with a grumpy, lazy and unwilling runner, who moans about their fifteen-minute lunch break, hides away when someone is looking for volunteers to move a heavy piece of set, and suddenly needs to leave just as the de-rig starts. They stick out like a sore thumb, and the rest of the crew won't be impressed at all. You will go much further if you are be happy to lend a hand, willing to get stuck in to everything that needs to be done, and are capable of taking on some responsibility, even if that means simple tasks such as escorting an actor/actress back to their car. (Depending on who the actor/actress is, this might be the best job of the day!)
Whether you are being paid or not, you will probably have quite a specific reason for being there. If you do have a role in the production, it is essential that you know what is expected of you, and that you remain focussed on your job throughout. There will be plenty of waiting around, so use this time to check your equipment and get prepared for your next cue. Be patient if you have to wait for other people to do their work, but don't hold up the entire production just because you want an extra five minutes to have a cup of tea.
Film and TV sets are fast-paced environments, so you need to be constantly aware of everything that is happening around you. Halting a production because you've tripped over a cable is the last thing that a floor manager or 1st AD (the person responsible for everyone's health and safety) wants to do. Health and safety is, and should be, taken very seriously, especially if there are dangerous stunts or heavy equipment is in use. It is everybody's responsibility to ensure that health and safety procedures are followed - and that includes you. If you see anything that you feel is unsafe, even if it is something as small as a loose nail, you must tell someone. Even if you can't tell the floor manager or 1st AD, tell someone who is close by, and they should react to what you are telling them.
If you can demonstrate your enthusiasm and professionalism on a film or TV set, and get through the day without breaking anything (props, equipment and bones included), then you will leave a good impression upon the people you met. The more willing you are, the more responsibilities you will be given; the more interested you are, the more you will learn; and, the more professional you are, the better your chances of being asked back on set.