Happiness is a choice
To me, attaining happiness is simple: choosing to be happy.
When you change your perspective on life, you change how you feel. Only you can make you happy. You choose to make your life the best it can be.
In life, you are in a war against yourself, against your own stupid mind, and you can win. You’re asking yourself “What’s the point in life? What’s the purpose?” But what you don't realize is that it's you. You are the point. You are the purpose. You give your life purpose. You find those points of interest in your life and you chase after them. Find what makes you happy and chase after it like a dog after a wild rabbit. Because I bet you anything that that dog is happy, and isn't concerned with all the existential things I mentioned. I guess what I'm trying to say is that in order to be happy, you need to quit focusing on the negatives. Realize that your potential is huge and you have the agency over it to make that potential be put to good use.
You are in control of your own fate, and you can choose to make it a happy ending.