The best advice comes from the people who have been through it. They have been around the block enough times to know the tips and tricks of the trade. They've experienced the good and the bad of whatever field they're in and they'll tell it to you straight. No one is more of a straight shooter than your coworker who has been there much longer than you and knows exactly what's up. It's important to listen to your elders.
There are nuances to the world of employment that don't immediately come when you sign your first work contract. There are subtleties and attitudes you have to pick up through experience, and the sooner you do the better off you'll be. Luckily we've collected some golden nuggets of wisdom about the working work right here for you. May it make you a better employee (Or actually just a happier person. That's more important).