Most important in my opinion is to always be open and talk about the topic of depression. When I was depressed during my teens I didn't talk to anyone, thinking that no one understands my problems and nobody cares. But after growing up and experiencing life, I understand now that nothing beats expressing your issues to an open ear. Sometimes saving all the issues at heart can cause unnecessary pain and guilt. By sharing with someone else, you are able to release the stress and get some feedback. In many cases, your problems are faced by similar people and they can share how with you how they solved them.
Channel your self hate into self abuse, but of the constructive kind. Like punish yourself by making yourself practice something (For example a musical instrument) you love, harder. Express your pain that way and soon you will be able to express it fluently and easily, and the process will feel rewarding.
My personal cure for depression was to just be active and sharing your feelings with someone else so that you know there are people out there who care about you.
At the time, I wasn't sure if it was depression or teenage hormones and growing up. Looking back, I was incredibly depressed, and I'm sure it was triggered by the neglect and other trauma I experienced at the time. I got so low I was planning on ending it. Luckily, I found something to live for. It has only been in the within the last 5 years I have accepted I need medication to regulate the chemical imbalance. It's a struggle, but now I understand it better and know the signs of an episode.