You're not there to show off your cool bullet-time technique or to suggest that every shot be handheld because you just got a new gimbal. No, you're there to work with the director to figure out how to shoot the film in such a way that it tells the story and communicates the emotion to the audience.
Robby Müller used 16mm and 8mm for a Hollywood produced film. The format was chosen for the image quality. Know if your physical tools match the hypothetical image. Craftsman and Technician fit into one roll.
Coffee for your department head and a smile for everyone else. Also if you want to be a super PA bring anything you would have on your own. if you have a viewfinder bring it. The dp might not have one and it be a quick way to get on a first name bases. Ever time on a film set think if you mess up it will be your last mistake. Always ask questions and if you are unsure DO NOT DO IT! Let some one else make the mistake. Creating is really really really hard so do not prevent the creatives from working. You are a tool to make their ( the creatives) vision happen. One day you can man the directors chair, but today you are the grunt.
Film unfortunately has plenty of gate keepers for those looking to become part of that industry. The only way these gate keepers will have you or anyone else pass through is by proving yourself. I have heard stories from producers, of staffers who literally walked in one day and said how can I work here. They handed them a list of contracts needed to be signed, and they went and did it. What ever part of the industry you want to join remember it is about proving your skills to that gate keeper. Ever opportunity is crucial, even the opportunities that do not work out.
If you are looking for a job in production you need to work at a production company. There are data bases for you to find your local production companies. My suggestion when you find them is to go in ( nicely dressed) and say how can I work here. No production company may be hiring. So volunteer get your name out there. If you can not volunteer make your own bloody production company. There are endless possibilities to make a career, you just need to learn where to look.