1. You show up early and stone cold sober. In your backpack is a stack of your business cards, a quart bottle of water, a couple of oatmeal bars, a small toolkit, a roll of gaffers tape, a small first aid kit, a yellow pad, some pens, pencils and markers, two cotton towels, a pair of clean sox & underwear, a t-shirt, a sweatshirt, some rainwear, a small flashlight, fresh batteries for your cell phone and a sleeve of AA batteries and a sleeve of 9-volt batteries. Wear a belt; if there is anything like a budget you'll have some place to hang things. If you drive get there with a full tank if you can. You now have potentially dozens of opportunities to save the day.
2. Do whatever job you are assigned to the absolute best of your abilities. Ask questions - there's no such thing as a stupid question. If you have some down time with no responsibilities offer to help elsewhere. If your help is not needed talk with someone else with nothing to do. Give him/her a business card, get one from them. If you have a moment or two make a few notes on the back about your conversation.
3. Eat the best food "health wise" that is offered (go for the bran muffin instead of the donut - LOL). Drink lots of water. Make sure that you dress for the weather, like, when it's 10 degrees out with a minus chill factor and you have to stand on a windy street corner for two hours.
4. Stay pleasant and stay positive the entire shoot.
4. Lend a hand wherever needed when wrapping for the day.
5. After wrapping for the day drink soda at the bar because you're still at work: networking, weeding out the wannabees from the other hard workers, getting leads for more jobs, handing out more business cards. Oh, okay, after everyone else is well along you can have one or two.
6. Go home. Replenish your bag. Have a good meal (if it's not too late). Relax for a bit. Get a good nights sleep.
7. Repeat steps 1 through 6.
8. When you're not working go to screenings. Yeah, lots of them are bad, but it's amazing how much money gets spent on bad. Network as best you can, observe rule #5.
The following is a true story. I have worked on numerous projects with a producer who has a way of attracting talent. In fall 2004 she put together a team to enter the NYC Midnite Madness Film Festival. The DP had done some indie film (real film), his business is commercial advertising, industrials, etc. The lighting was provided and run by a local commercial photographer. I did production sound and audio post. The acting talent was local theatre-lo/no indie types. And there was our PA, Abram. This was 19-year-old Abrams fourth gig as an unpaid PA. Our producer met him at a screening and got a good reference.
Abram stepped in and took responsibility for all of the tape logs for the camera and the DAT. He spoke up whenever he saw a continuity snag. He held a second boom for me. He was a focus puller a few times. He helped move lights. On the second day he even suggested a shot, which we used. We all had a very good time with him during the shoot and the following weekend at the wrap party. Our second place finish was due in large part to Abram.
Because Abram worked his butt off he got a call from the DP a few weeks later; Hans needed a last minute one-day replacement for a job on his set. Six months later he was Hans' right hand man at all his shoots. A year later Abram got a gig as a Key PA on a well budgeted indie project. He later worked, although I don't know in what capacity, on the "I Am Legend" set in NYC.
By working his ass off Abram got very far very fast. You may not get quite as lucky, but people always remember hard workers with a positive attitude.