Note: These are not tips on being a GOOD employee. In fact, if you're a good employee you probably don't need these tips nearly as much as the rest of us. But I realized today that I have picked up some skills along the way that are difficult to practice, but that can really help you.
1) If you say you're going to contact someone, do it, even if it's just to say you didn't do what you said you were going to do.
People hate being ignored on a personal AND professional level, whereas they only hate being behind on a professional level.
This is one of the toughest things to do for me. The fantasy is that "maybe they forgot." They didn't forget. Call them and tell them they aren't going to get what they were expecting. Half the time you'll find the person is relieved they don't have to do their end of things right then.
2) If you screw up, take ownership of the mistake BEFORE someone else blames you for it.
This is so crucial, and it took me several jobs to discover it. Not only will your boss or coworker appreciate this behavior for its own sake, it puts you in a position to be able to suggest ways to avoid the situation in the future WITHOUT your suggestions sounding like excuses.
2a) "I screwed up, BUT..." is not taking ownership of your mistake.
In fact, it puts your boss or colleague in the position of having to tell you that your screwup was unacceptable, even though you admitted screwing up. It's the worst of both worlds. It's hard to say "I screwed up, and I need to do better" and leave it at that, but when you do it you'll find that's often the end of it, as long as you don't make it a habit.
3) When someone else makes a mistake, it is not necessary to blame them, or even to mention them.
This is somewhat unfair advice for me to give because my boss is very astute. She knows whose fault something is. So if something gets screwed up and I say "I should've double-checked it" she knows that in reality the mistake was made by the person who did it, not the person who didn't check behind them.
If you have a bad boss, you may feel the need to point out when something is someone else's fault. The problem is that your coworkers will of course also feel the need to do this. Eventually you will find yourself in a terrible work environment. The other problem is if you have a bad boss, he's not making decisions on any rational basis anyway, so you might as well keep your soul intact. In the end he's going to act like an ass no matter what you do.