1. Getting along with your co-workers is just as important as doing your job
When you arrived on your first day, you may remember being both excited and nervous. Who would your new co-workers be? What would they be like? For 40-plus hours a week with your new "family," making a good impression and forming relationships made work easier and more fun.
This remains true throughout your career, no matter how many times you change companies or jobs. You still have a "work family" that you spend much of your time with, and it's still important to keep that family strong. When you're close with your co-workers and have established a trusting relationship, everybody works harder and more efficiently.
2. Paychecks are for both fun and for saving
There's no thrill quite like receiving your first paycheck. It's a step into adulthood as well as a step toward the finer things in life. Suddenly, a nicer wardrobe and a new ride were deemed just as important as paying your bills, and saving money may have been a struggle.
Getting smarter with money doesn't come naturally with age -- it's a discipline that takes practice and effort. Bills and practical purchases should take priority, and so does saving for the future. However, remember the excitement of your first paycheck and the validation it gave you for taking the job, and celebrate your hard work with occasional fun purchases.
3. Listen to and learn from your peers
When you started your first job, you had to adjust to your new co-workers, and you also had to rely on them to show you the ropes, answer your questions and support your efforts.
Maybe you're no longer the "newbie," but you should listen to and learn from your peers just as much today as you did on your first day. Everybody you work with was hired for a reason, and everybody is an expert in some area. Not only can you take advantage of these areas of expertise when you have questions, but you should also return the favor and be just as helpful to them as they were to you. Make an effort to keep close working relationships with your co-workers, and create a strong, capable team that's ready to help the next new guy.
4. Always be prepared for meetings
The first several meetings you were invited to probably felt more exciting and special than the ones you attend now, though that's not a good enough reason to show up unprepared. It's easy to fall into the habit of "winging it" at meetings, arriving without ideas to contribute or reviewing any materials. Not only is this disrespectful to the person who called the meeting, but it slows down the productivity of the meeting as well.
When you first began working, you likely felt an urge to prove your worth, so you went over the materials, came prepared with thoughts or ideas and contributed to the meeting in any way you could. Such a helpful attitude only makes you look better as time goes on. Don't fall for the misconception that experience means you don't have to try as hard.
5. Your job isn't a sure thing
The first week on your new job was filled with hesitant moves: "Am I allowed to do this?" "Is this OK?" "Will I get fired for this?" As you settled in, you realized how silly some of those thoughts were, and it was unlikely you'd get fired for that extra five minutes you took for lunch.
Fast forward to now, and you're confident that you have earned enough freedom to do what you like, as long as your projects are finished. That mindset may lead to trouble, though. No matter how long you've worked somewhere, your job isn't 100 percent secure. You're working for others, and you need to meet their expectations first.