Talk to a professional, such as a therapist.
Make time for people who have a good impact on you.
Physical contact is good to release certain brain chemicals that relieve depression.
Thinking positive and realistically, trying not to focus on the negatives. Maybe writing down the negative thoughts- then writing the positives down beside the negative thing you wrote.
Compliment yourself and write a small list of things you love about yourself.
Be open with your thoughts and be positive. Try your best to think positive but if you have a negative filter try to cope with it.
Focus on your health: exercise, eat healthily, avoid any drugs or alcohol, sleep good hours,
pick a hobby that you enjoy.
Go outside, meditate, take care of an animal, volunteer