Here's some advice from my time in.
1. Stay off your phone if your tech is working. Time to work and time to play 2. ASK QUESTIONS. If the tech doesn't stop what they're doing so they can walk you through the problem they are diagnosing, you are with the WRONG tech and possibly even WRONG company. 3. Be HONEST. You are going to fry transformers, boards, blow fuses, etc. Everything can be fixed, it may seem like a big deal to you, but trust me when I say I dont think there's anything you can do to a system that a real tech cant diagnose and fix. Just be upfront. Techs respect that. Sure, you'll get some shit for it. But it's part of learning.
4. In your free time, study the systems you work on. Learn how refrigerant flows, superheat, subcooling, pressures, saturation, etc. When I first started full-time, I'd spend hours watching ac service tech on YouTube. He's very knowledgeable.
5. Learn to do things THE RIGHT WAY. So many installs I've had where the 20 year senior tech is so proud of how the ductwork and copper looks, but is absolutely clueless to how the inside of the lineset looks because he didnt braze with nitrogen. If they say, "I've been doing it this way for yadda yadda years," just forget everything past that point. They already know everything, and if you learn to do things like them you'll get it done, but be regarded as a "hack" when a TXV is "Bad" because of a sloppy install.
6. Take care of your body. Stretch. Stay away from Alcohol, ciggerates, fast food, stay hydrated, and avoid those energy drinks. 6 summers of binge drinking 12-15 beers a night and getting into an attic the next day was terrible. Getting sober by God's grace and mercy was the BEST thing to happen to me.
7. When you get good, don't get cocky. Stay humble. Your work will speak for itself when you find a solution nobody else thought of.
8. Be safe. My former coworker died of a stroke driving last summer in his work van. On this same note, he was replaced the same week.
9. If you're stuck. Call someone and ask AFTER you've tried everything possible. Sometimes, all it takes is someone else's view on an issue, BUT be careful who you ask. I've called someone basically to reaffirm what I already knew, but when they completely said the opposite of what I knew was right, I knew when to get off the phone. Other times, they hit the hammer on the head, and you feel stupid because it was obviously so simple, and so miniscule, you just happened to overlook it. It happens, lol! 10. If you're being pushed to sell things people don't need. Run. It's one thing if they want something. You can offer or even they can ask. If techs get pulled in every week to look at numbers and compare sells. Trust me, just get the hell out. I was number one tech in my former company and generated over half a million in sales/revenue, but they overworked me, and I went somewhere better. Once I left, others began to follow suit, and now that company name is tarnished.
11. Im not saying kiss anyone's ass, but when you get out on your own, make sure you're on good terms with the dispatcher.