1. You have to advocate for yourself; you can't count on others to do it for you. Too many workers assume that their company will notice their talents and accomplishments and reward them through raises, promotions, or better assignments. And while this certainly does happen, it's naïve to rely on it. Instead, assume that you're your own best advocate, and that you'll need to speak up—whether it's asking for more money or tracking your accomplishments throughout the year to raise when your performance review comes around.
2. Your reputation matters—a lot. People sometimes wonder why they should work hard and go out of their way to excel at work, when their employer may not show them the same commitment. The reason? You're not doing it for your employer; you're doing it for yourself. Building a reputation as someone outstanding at what you do means that you're creating a safety net for yourself: You'll have people excited to hire you when you need them to be, former managers clamoring to recommend you and connect you with job openings, and the ability to command more money. Conversely, if your reputation isn't good, it will become increasingly hard to do the things you want with your career. So it's key to cultivate and protect your reputation; it's one of the most valuable currencies you have.
3. A bad boss can ruin the greatest job. You might love your work passionately and adore your co-workers, but if you have a bad boss, none of that will matter. A terrible manager can make your daily life miserable, so it's crucial to assess your likely management before accepting a job. Don't get so excited about the work you'd be doing that you miss danger signs about the person you'd be doing it for. Speaking of which…
4. There's no such thing as a dream job. Or, at least there's no such thing as a dream job that you can spot from the outside. As much as you might think that you'll love a particular job or to work at a particular company, you never know what it will really be like until you're there. Legions of people have discovered that their "dream job" came with a nightmare of a boss, or awful co-workers, or hours so long they could barely see their family. And feeling that an opening might be your dream job can lead you to miss crucial danger signs during the hiring process—causing you to accept a job that turns out to be nothing like your dream.
5. Your degree might not help you as much as you thought. College and graduate degrees no longer open doors the way they used to, and too many new graduates are surprised and frustrated to discover that even with a degree, they have trouble getting the jobs they want—or, in many cases, any job. Work experience is more and more crucial, and students who don't start getting real work experience before they graduate are at a significant disadvantage. This is a tough lesson that you can avoid if you plan early enough—and it would help if schools and parents started helping students see this too.
Alison Green writes the popular Ask a Manager blog, where she dispenses advice on career, job search, and management issues. She's also the co-author of Managing to Change the World: The Nonprofit Manager'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.