As a congratulations gift for landing my first job, my mom gave me more pearls of wisdom. In the few days before I started working, she drilled what she considered to be essential work etiquette into me.
1) "If your co-worker or your boss is explaining something to you, you nod, you smile, and you show appreciation. Even if you already know what he/she is teaching you, you still show gratitude towards him/her. You never say "I already knew that." No one likes a know-it-all. You want people to help you in the future, you make them feel good about helping you."
2) "You have to think ahead, don't be like a bead on an abacus. Use your common sense. If your boss tells you to wipe down the display, look around when you are done. What other surfaces need to be wiped down? You don't have to wait for your boss to tell you. If you see the glass door has hand prints on it, or the refrigerator doors have smudges, then wipe them down as well."
3) "Keep yourself busy at work. Your boss is not paying you to sit around. You can always find something to do. Don't do personal stuff when you are at work, not even school stuff. Work is work. Your job in school is to study, your job at the bakery is to work. If you are constantly working and moving, your boss will be more forgiving towards your mistakes. If you sit around a lot, well, your mistakes will be magnified because you haven't done a whole lot."
4) "Always smile. Smile at your co-workers, smile at your boss, smile at your customers. No one owes you a dime, they are not obligated to deal with your personal problems. Keep your problems to yourself. Your co-workers want a pleasant work environment, you boss wants a cohesive team, and your customers want good service. So bottom line is, who cares about how you feel, you smile at others."
5) "Show your work through your actions, not through your words. Don't boast about your abilities. A good employee is one who does a lot but says very little. You may be dumb, but you can make it up by being diligent, pleasant, and humble. These are priceless qualities as well. No one wants to help out a braggart."
6) "No matter what your co-workers say, do not complain about your boss or your work. You don't like your job? You can find a new job, but don't complain about it. If you don't have the ability to find a new job, then learn to deal with your job, but still don't complain about it. You don't like your boss? Well, too bad, he/she is your boss and gets the final say on everything. Work hard, study hard, then one day, you don't have to have a boss."