After walking this earth for almost twenty years, I've learned many things about life, humanity, surviving and how the world works. I've learned that life moves on, whether or not you choose to move with it. I've learned that no company is always better than bad company. I've learned that you will always reap what you sow, in some form. But most importantly, I've learned how to be alone. Although my sibling-less childhood may have given me the foundation, being single for the better part of my adolescence has taught me how to fail at being on my own and how to successfully be my own person.
Decide what you want for yourself (solely for yourself) and go after it. Whether you're in college and you're trying to complete your degree, you're in graduate school going after a Master's, Ph. D., etc., or you're in the working world and you want to get ahead in your career field, go for it. If you want to lose weight, work out more, or just eat healthier, try it out. If you want to write a journal, a novel, a thesis, or whatever, write it. Set goals that are for you and only you, that revolve around your own happiness and well-being. Set out to be your best self for you.
Make sure you're feeling your best and taking good care of yourself. Laci Green put it better than I ever could: Self Care is extremely important.
Go out by yourself. Whether you study abroad or you just grab a coffee and sit in a park, sometimes going out by yourself can be one of the most freeing and relaxing experiences. Although it is nice to go out with friends, sometimes it's nice to just go out on your own and experience the world on your own.
Step outside of your comfort zone and don't care what anyone else thinks. Do something that you've always wanted to do and don't care if you completely suck at it at first. Whether it's a dance class, knitting, writing, or any other hobby you want to pick up, try it out for yourself. Keep at it, you never know what will come of your skill.
Strive to make yourself happy before trying to make anyone else happy. You have to be at peace with yourself before you can try to help anyone else. So do things to make yourself happy before trying to please everyone else.