Here's a miscellany of tips that will serve you well. Some of these are fundamental, but they bear repeating. Below that is a special section, all about walkie-talkie ettiquette (learn these guidelines, and they can save you a lot of grief!)
Do's and Don'ts of Set Life
DO read your call sheet thoroughly. Read it. Learn it. Love it.
DO write things down in a notepad, instead of just relying on memory.
DO make friends with your colleagues.
DO have a thick skin - you will get yelled at by someone, at some point. As the philosopher Taylor Swift said, shake it off.
DO listen to the walkie-talkie chatter. Every once in a while, it WILL pertain to you.
DO observe the chain of command on set.
DON'T leave coffee or open drinks anywhere they could be knocked over.
DON'T plug anything in without asking the gaffer or an electrician first.
DON'T touch property from other departments, unless you've been asked to help.
DON'T email the AD with a question unless you're absolutely certain it's not addressed on the call sheet.
And in any and all matters of safety, if you see something, say something.
Walkie-talkies are a necessary evil, in my opinion. They don't always work very well, but we would be lost without them. Here are a few ettiquette guidelines, and a few warnings.
1. Listen to all the chatter on the walkie, because even as a lowly PA, every once in a while someone will call your name.
2. Often the AD will ask for something to the PAs at large, like "Can someone find out who drives the silver Honda Civic that's blocking in our grip truck?" You can be the PA who takes initiative and gets on the task right away. ADs love it when things happen right away.
3. This is how a walkie conversation should go:
JOHN: "John for Mary"
MARY: "Go for Mary"
JOHN: "We found the owner of the Honda Civic. He's moving his car now."
MARY: "Copy, thank you."
Announce yourself and who you need, then that person responds "Go for [their name]." The conversation stays short and sweet, and the person says "copy" to confirm that they heard what was said.
For conversations requiring more depth, it's best to go to an open channel. The call sheet should say which channels are used for which departments, and which are open. If it's going to be a longer conversation, tell the other person to go to 2, or which ever open channel you're switching to. There will be a dial on the walkie to switch the channels, or there might be a digital menu. Switching to an open chanel keeps the main chanel free for other communications. When you're done, make sure to switch back to the main channel.
4. There's usually some shorthand used over the walkies, like:
What's your 20? = Where are you?
Standby = I can't talk now, but I can in a minute
Going 10-1 = taking a bathroom break
Eyes on the director? = Does anyone see the director?
Copy = I heard you, or, I'm on it
A hot brick = a charged walkie-takie battery
5. After you press the 'talk' button, wait a half-second before speaking, because it takes a moment for your walkie to start transmitting after the button is pushed.
6. Make sure you don't accidentally auto-key your walkie, meaning that you are transmitting continuously. This can happen if something accidentally presses the button, or even if you plug in the headset while the walkie is powered on. It's best to power the walkie off before you plug or unplug the headset, or before you change the battery.
7. When you power on or change the battery, ask over the walkie, "Good check?" and if it's working properly, someone else will say "Good check." Then you know you can transmit and receive properly.
8. Walkie-talkies are usually numbered so production can keep track of all of them, and know who last had a certain walkie if it goes missing. Sometimes they will let you take the walkie home, especially if you're coming back the next day, but sometimes you have to turn it in at the end of the day. If that's the process, don't forget to turn it in!
For more on walkie-talkie survival skills, here's a great article from HowToFilmSchool.com!