It is as simple as doing something.
Go for a walk and pay attention to the small things. Ants, architecture, flourishes. It will activate your brain matter.
Build something. A productive hobby releases dopamine in levels not matched by passive entertainment. Video games don't count as a hobby. Collect bird feathers if your are poor. Try to id's tify their source.
Exercise greatly reduces depression and boosts self worth. Even if you are a fat fuck, exercise gets your body to trick your brain into thinking life is good.
Take a break from porn and the internet, especially any type of social networking site. Both are designed to overload your senses. A constant barrage of stimulation lowers your ability to take joy in stimulation, deadening the world around you.
Good luck faggot.