Congratulations! After months of preparation and anticipation, you finally are starting your MBA program. An MBA is a huge investment of time, effort, opportunity cost, and money that perhaps 100,000 people worldwide make every year. That investment in yourself can pay great returns over your career, especially IF you avoid these seven mistakes that full-time MBA students can make.

1 - Remaining in Your Ruts - By the time you are ready for an MBA, you probably have developed your style at work. Maybe you have focused on a few strengths because they cover your weaknesses. Maybe you have been typecast into roles. Maybe you have developed some bad habits that you have found hard to shake. Maybe you have been too risk averse to try different roles. The good news is that your MBA experience gives you a chance to reinvent yourself - perhaps like college was a chance to grow beyond your high school self. Your reputation will be a blank slate to your classmates. Your habits have to change as you go back to being a student. You are probably looking for a new job when your MBA is done, so it gives you some freedom to try new things too. An MBA can be a perfect chance to make changes.

RECOMMENDATION => Set 3 goals about things you want to start, stop, change, or try while you are getting your MBA.

2 - Being Too Shy - An MBA is an extraordinary and unique time in your life to build your network of professional contacts. Your classmates will come from a broader spectrum of backgrounds and future interests than you had with your past workplace. Imagine going into the future and being at your 5, 10 or 20 year reunion. How many of your classmates will have experiences and roles that would make them people you would want to know? The good news is that your shared MBA program should make it easy to make those connections. You all share an experience and you all are starting at the same place. And if your MBA program happens to be on a campus with many other graduate and professional programs (e.g., medical, law, engineering, etc.), find chances to meet your peers there too. Even try to get close to at least a couple of your favorite professors. View your MBA as an opportunity to plant seeds in your professional network that will sprout suprisingly wide, deep, and tall in many interesting places in the future.

RECOMMENDATION => Set a goal for yourself on how many new LinkedIn connections you will make each week/month among your MBA classmates and other people on campus.

3 - Underpreparing for First Job Interviews - Since your MBA is such a big investment, you need to get a job that will help you pay that off after you graduate. Getting ready for job interviews is key. If your program has a summer off for internships between the two years, getting a good internship job there will make the rest of your MBA much less stressful. Do not assume that your success in interviewing before will carry you, however. Job interviews at the MBA level can be quite different. Case interviews, for example, require unique skills that are not easy for the inexperienced but can be improved through practice. Practicing for interviews is not like studying for tests, though. You should practice out loud, with others, so you can hear yourself. Maybe even video yourself to see how you come across to interviewers.

RECOMMENDATION => Treat job interview preparation as a class of its own. Carve out the time on your study schedule. Work with others. Set goals for how many practice interviews you will do and what success will look like for you.

4 - Making Enemies - Some competition between MBA students is natural. MBA students tend to be driven to get them best out of themselves. That may spill over into a competitive drive with others for things like grades and talktime in class. Competition can come to a head with job interviews. If you ever find yourself tempted to think your chances of getting a desired job would be increased by decreasing your classmates’ chances, immediately stop yourself before you do something a classmate might resent. The post MBA world is much smaller than you think, especially with social networks like LinkedIn. Before you do or say something to or about a classmate, imagine them at an organization that you are trying to work for in the future. What would you want them to say (or not say) about you when a hiring manager sees on LinkedIn that you were classmates and asks if they should interview you?

RECOMMENDATION => You don´t have to be friends with everyone in your class, but don´t leave with anyone mad at you, if you can help it.

5 - Settling for Bad Professors - If your MBA program is big enough, you may have many options on classes and professors. There may be multiple professors teaching the same courses. Some professors are always going to be much better or worse than others. Do whatever you can to get into classes with the best professors, or at least avoid those with the worst professors. Years later, you will have forgotten much of what you were taught in class, but the things you will still find useful will have come from the best professors.

RECOMMENDATION => If there is one place where it is worth being a squeaky wheel with school administrators, switching professors may be it. I remember how my classmates and I got my business school to help with an ineffective new professor when we made a compelling case. They just added seats to the other professor’s class to give us an option. It was not ideal, but much better for me than having an unacceptable experience for a key course.

6 - Skimping on Summer Vacation - If your MBA program has a summer break built in, take the fullest advantage of it you can. Build in some time before or after your summer internship for a vacation. It may be your last chance to get more than one or two weeks off in a row to do something that requires extra time, like travel or an extracurricular project. It can be hard to get extra long vacation breaks after you start your new job.

RECOMMENDATION => Plan your summer ahead so you can carve out time you want. Your summer employer might have some flexibility on your start/end dates. If you have a worthy-sounding reason for asking for more time, you are more likely to get it.

7 - Taking it too Serious / Not Seriously Enough - Being a full time student is a much different experience than working full time. There are things that can be stressful - like difficult subjects, getting homework and grades all the time, and having to form new relationships. Keep those in perspective and don´t be afraid to ask for help when you need it. There are things that are liberating too, like being your own boss and having a much more flexible schedule. Enjoy those, but keep the discipline to treat your studies like the job it is. If you find yourself treating it like a vacation, change your routines fast.

RECOMMENDATION => Identify a few friends inside and outside your program who you can check in with on a regular basis to get feedback on how you are doing.

I look back on my MBA experience as one of the best times of my life. It was a great investment in so many ways. Perhaps it could have been even better if I had had this advice. In particular, what if I had been less shy and met more people at the broader University of Pennsylvania community? What interesting connections would I have in my LinkedIn network now? I say this because Elon Musk was also a student at Penn at the same time as me. How cool — or maybe even life-changing — could it have been for me to strike up a conversation with him while waiting in line for lunch at one of the food trucks? What future inventors, CEOs, or other leaders will be standing next to you at school?