It's not too late to avoid these mistakes.
1. Trying to impress others
If you spend your life trying to people-please, you will never be satisfied. You cannot please everyone. It is impossible. Also, you don't have to! It is not your job to exalt yourself to meet other people's impossible standards. Hint: they probably are not near as concerned with your life as you imagine they are.
2. Not taking care of yourself.
Physical and mental health are so important for your health and general well-being. Exercise can actually boost your mood by releasing endorphins, which positively affects your mental health. It is a cycle of complete good. You have to live with yourself the rest of your life, so take care of your body, mind, and soul.
3. Giving up.
Whatever it is that you are trying to accomplish, chances are that it is hard. If it was easy, it would be done and everyone could do it. Keep pressing forward, though. Giving up is not going to make whatever it is happen any faster, it will only slow you down and hinder whatever progress you've already made. You can do this, and you will.
4. Settling for less
Life is too short and too hard to settle for less than the best that life has to offer you. It is not meant to be an endless, monotonous routine of "okay" moments. Have the courage to change your circumstances and strive for better than "okay" in everything. You deserve the best, so go get it.
5. Keeping toxic people around.
Nothing will drag you down faster than toxic people. Their negativity will infect you without you even realizing it is happening. It is also not your job to fix them. There is no amount of effort in the world that can change another person's behavior. You can, however, change your own and decide that your time is not well-spent will people who bring you down.
6. Living in the past (or the future.)
Unless someone hasn't told me that time traveling exists, it is impossible to go back and change something that you said, wish you had said or did. What is done is done. You can learn from it, but you have to move on from it as well. The same goes for living in the future. That will only bring on anxiety. Live in the present--it doesn't last long.
7. Staying still.
Life is fluid. Embark on this wonderful journey with a mind and heart willing to accept change as it comes to you. If you don't embrace the fluidity of life, you are not allowing for personal growth. You were not put on this earth to merely survive day to day.
8. Taking rest for granted.
We live in such a fast-paced world that so many of us are afraid that if we slow down, we will get run down. Just the opposite is true, though. It is of vital importance that you take time every single day to recoup. Rest affects your general health. (See number 2.)
9. Lying to others and yourself.
There is no possible situation where lying to someone affects the outcome in a positive way. Honesty can be difficult, even brutal at times, but it is always the best policy.
10. Neglecting your own happiness.
I think that women are more prone to do this than men. It is our job to take care of everyone else that we often forget the most important person that we should be worried about--ourselves. There are 24 hours in a day; save at least one of those hours to do something that makes you happy. It will change your whole day, I promise.