Accept yourself for who you are and love yourself. You must learn to look in the mirror and love what you see, the image of who you are. Loving yourself is the first step towards happiness.
Make peace with your past. Forgive those who need to be forgiven. Cut ties with those who cares nothing about your happiness. Surround yourself with positive, uplifting people who motivate and inspire you.
Do not harbor bitterness or resentment in your heart towards anyone because in the end it will stifle your inner growth and peace of mind.
Be kind to yourself. Pamper yourself every once in a while. Do something that makes you happy and make it all about you, you deserve it.
Learn to say no. Remember that you are not here to save the world, so do not take on more than you can handle because you might not want to displease someone. You are never going to be able to please everyone or be everything for everyone. You must be able to say no and feel no guilt about doing so.