These two components are valuable to happiness, in my experience:
Know yourself. Be self aware, including an awareness of your flaws, and a constant search for self-betterment. Happiness doesn’t come from deluding yourself into thinking you’re perfect; it comes from accepting that you’re imperfect but always trying to be better. Not to a self-destructive extent, of course. Or, if you can accept and be happy with who you already are, flaw and all, that’s great too. Do things that you can feel proud of.
Love yourself. I don’t mean be an arrogant prick, but try and treat yourself well. Pay attention to your physical and mental needs and don’t jip yourself of them. Identify what hobbies or environments make you happy and set aside time to indulge…don’t work yourself to death.