no really life hacks, but some must know advices:
1) reduce your relationships to the minimum: no "friends", and no girlfriend to cause you any trouble. Only your family (if you like your family). I'm much more happy when I'm alone.
2) constantly learn new things with, as a motivation, self-satisfaction. Count on yourself to be proud of yourself. by learning new things, you'll improve your self confidence, and people will see you as a really smart and accomplished person. Don't expect others to make you happy.
3) save your money. don't spend it to conform to fashion trends. only spend it if you really need something and there are no workarounds. (for example, if your phone is still working, but slowly, reset it instead of buying a new one, and if it's not enough, you can buy a new one, but not for a $1500 smartphone). Keep things if they are still working. With all your money saved, if you don't have any debts, you will feel free.