1. Doing your job adequately is enough. Doing a merely adequate job isn't enough these days. With so many qualified job seekers available for hire, you need to go above and beyond to be seen as valuable. If you're simply meeting your employer's minimum expectations, your boss can quickly find someone who will do more.
2. If you do good work, your attitude doesn't matter. If you complain frequently, regularly shoot down ideas, or act like the office prima donna, your boss probably considers you a pain. And that will probably result in less interesting assignments, less flexibility, lower raises, and a higher chance of ending up at the top of the list if cuts ever need to be made.
3. Asking questions about an assignment will make you look like you don't know what you're doing. Good managers want you to ask questions, because they want you to get it right and not make mistakes that could cost time and money. In fact, it's generally unnerving when an employee who is taking on new work doesn't ask questions about it. Managers want to make sure that you're on the same page as they are and asking questions is often essential to getting there.
4. Being liked and making friends at work is more important than doing your job well. Few people would say this outright, even to themselves, but many people's behavior shows that they do believe this: They chit-chat when they should be working, they don't assert themselves when work is done incorrectly, and they gossip about the boss when doing so could destroy their own relationship with their manager. Bonding with your co-workers is great, but not at the expense of your reputation or your job.
5. You don't need critical feedback. If you get upset, angry, or offended when your boss gives you feedback about your work, you're doing yourself a disservice. If nothing else, it's in your best interest to hear your manager's concerns. If you're focused on defending yourself, you'll miss out on the value of what's being said. And if your manager happens to be right, blocking out her input means that you'll deny yourself the chance to get better at what you do.
6. Playing online during the day won't affect your work. If you're using social networking sites, instant-messaging, or browsing online sales throughout the workday, it's probably impacting your performance. Sure, you might get the basics done, but you don't want to just do the basics—you want to build a stellar reputation as someone who routinely exceeds expectations. And if nothing else, spending a lot of work time online will create the appearance that you're not working hard, whether or not it's true.
7. If you make a mistake, you should make sure people don't know. Everyone makes mistakes from time to time; what matters is how you handle them when you do. If you don't accept responsibility or—worse—if you try to cover up that a mistake was made at all, your boss will likely be far angrier at this than at the mistake itself. Instead, acknowledge it, explain why it happened, explain what you're doing to fix it, and ensure that it's not repeated.
8. Your work speaks for itself. You could do great work, but if no one knows about it, you might not get the credit you deserve. When you meet (or exceed) a goal, or get a grateful email from a customer, or resolve a sticky situation with everyone happy, make sure that your boss knows about it.
Alison Green writes the popular Ask a Manager blog, where she dispenses advice on career, job search, and management issues. She's also the author of Managing to Change the World: The Nonprofit Leader's Guide to Getting Results and former chief of staff of a successful nonprofit organization, where she oversaw day-to-day staff management, hiring, firing, and employee development.