I used to be an addictions treatment counselor in a methadone clinic, so I'm going to answer for that because I'm still feeling my way through my new career a bit.
-If at all possible, try to attend to the suboxone patients first as their dose tends to wear off faster than the methadone patients
-Communicate very clearly to patients that you absolutely do need to know their rec drugs of choice (this is for multiple reasons but most of all because you can't send a high-tolerance benzo addict to detox)
-Keep an eye on anyone at the dosing station, ask them to set down any drink they brought in with them if they're a methadone patient, keep an eye on their hands/mouth if they're a suboxone patient (so they can't pocket their pills)
-Almost every single patient will be dealing with either chronic pain or mental illness, or oftentimes both. Keep that in mind when interacting with them
-The clinic that hires you most likely won't have a protocol for what to do when a patient has a panic or anxiety attack. Use your training to come up with how to handle it, and keep in mind that patients with PTSD need to be handled differently than those with generalized anxiety
-Actually get to know your patients as people, talk to them about their kids, their family, their job, their life. This will help you understand what's special about their situation so you can take into consideration the obstacles that they may be facing that others might not be. It also gives them the basic decency of, y'know, being treated like a person
-Get good at diffusing situations and handling aggressive behavior. If your city is small then a lot of these people ran in the same circles and some will have bad history with others
-MAKE SURE YOUR BOSS HAS THE PANIC BUTTON TESTED REGULARLY
-Nothing can prepare you for when a patient dies, goes missing, goes to jail, or drops off the program. It will happen at least once and almost definitely more. It's okay to get emotional about the people you work with but you have to learn to not let it affect you too much
-And on that note, a lot of these people have really sad backgrounds and it will hurt you to hear it. You'll need to find your own way to cope with this, you'll also need to determine who is and is not a pathological liar
-You will most likely not have to do induction with the patients, but if you do, keep a garbage bin nearby because 3/5 suboxone patients vomit the first time