I wouldn't presume to preach this as absolute truth and/or the surefire way to achieve success. These are just some things that I've found helpful along the way, be it in the office, in circle of friends or just life in general.
Sit, listen, observe, learn.
People love to talk, and they tend to talk about what they think is important if you don't steer the conversation in any particular direction. So, if you're in a new environment and you want to get acquainted with the situation and the people, just sit let the people talk. Observe as they interact with each other and learn the ropes. As a bonus you'll also pick up a lot of gossip without getting a reputation for being nosy.
Even when you're not confident whether your action is correct or not, if you decide to act - act decisively. Don't overthink make a plan and stick with it. It goes a long way. No one likes people who hesitate or back down when things don't go their way. Power through it, and if in the end you don't succeed, at the very least people around you will know that you're no slouch, and they can depend on you.
Don't be ashamed to ask questions.
If you feel the need to clarify something or don't quite know how things work - go right ahead. Sure, someone might crack a joke or two at your expense for asking them, pay no mind to them. Get the answers you need and suffer few jokes, It's better than not to ask the question and be made fun of for looking like an incompetent know-it-all in the end.
Admit your mistakes every now and then.
Mistakes happen. We're all human. Plus if you fess up to some of your lesser failures people might give you a pass if you keep your mouth shut when you fuck up good & proper. On account of you being the 'honest guy/gal' who'd "admit it if it was his/her fault." ;)
Society doesn't owe you anything.
You had a tough day/week? You have a difficult background? Well guess what, it's not society's fault. You don't get the preferential treatment, and if you do - it's just the good-will of the people around you. They don't have to give you a break, they just feel like it.
Be loyal to someone and earn someone's loyalty.
It's a rare thing to come by these days. And earning it requires sacrifice and selflessness on your part. If you're helping someone out and expecting something in return - you're doing it wrong. That's not how it works. The real loyalty is more than just an obligation to pay someone back for something they did for you. To be honest it's kinda hard to put it in words. But it helps you grow as a person.
If you want something from someone - ask for it.
No one can read your mind. If you don't open your mouth no one will know. It's not a guarantee you'll get it, but it's still better than sitting and hoping that it'll fall out of sky.
Courtesy is owed, respect is earned.
Be polite, but remember that no one deserves your respect by default.
Express your opinions.
You shouldn't be ashamed to express your views. They're part of who you are, if people around you don't like the way you think you've surrounded yourself with wrong people. This is not to say that you can't be wrong about certain things, but being wrong and being shunned for being wrong are two different things. Friends will help you see the error of your ways, or see the error of theirs if they're in the wrong.
Venture out of your social comfort zone.
Hang out with people from different social background than yours. Meet new people, go with the flow and see where the evening takes you. It gives you perspective teaches you new things and lets you learn how other people think and what makes them tick. It's also a chance to do some stuff that's considered a big no-no with your usual crowd. To put it short it's a liberating experience.
Stressed? Drive around the town at nighttime.
Soothing music and leisurely ride on the outskirts of town at nighttime can be an excellent stress relief. Traffic is nonexistent, lights are low, it's quiet on the streets. Your lower brain automatically switches into "let's-not-die-in-a-car-crash" mode without your conscious mind even noticing and all your worries fade away. Don't have a car - invest in one. It's a money well spent either way.
Anyways, these are things I felt like sharing with you, my fellow G@Gers.