There is no "magic bullet" that works for everybody. There is no magic formula.
And keep in mind the words of William Broad.
There is nothing fair in this world.
There is nothing safe in this world.
And there's nothing sure in this world.
And there's nothing pure in this world.
And yet there's something left in this world.
What might work for you will depend on many things. For example, your age, your gender, your family and social situation, your health, and a bunch of other things will have big influences on how you think about such issues.
There is an approach that works for many people. And it is very roughly this. Find something that you think is meaningful in some way. It does not have to be final-answer meaning-of-the-universe type of meaning. But meaningful to your life, or to your relationship with somebody you care about, or to some aspect of your culture or society that you care about.
You can often get hints like so. If something makes you smile when you encounter it or think about it, go have a closer look. If something makes you angry when you think about it, go have a closer look. These are signs that you have values that are either existing and you like it, or not existing and you don't like it.
When you have a candidate, study it for some time to be sure you understand it.
Do you love music? Maybe you should be a musician. Do kittens make you smile? Maybe you want to be a veterinarian. Or a pet shop owner. Does learning make you happy? Maybe you want to be a teacher or a professor. Do books make you smile? Maybe you want to be an author. Does seeing somebody get beat up make you angry? Maybe you want to be a police officer. Or maybe you want to study criminology and how to prevent such crimes. And so on.
Once you have found something that seems to be meaningful in some way, find the biggest possible task related to it that you could reasonably hope to achieve. And work at that task. Figure out what the heaviest burden you could reasonably carry is. And carry it. This will require some planning, since you can't just step into such a load, you will have to train into it. Maybe you need to go to university, or get a junior level job in the area, or start with asking her to have coffee with you. I hope you get the idea.
For many people this is the source of meaning in their life. And the source of the greatest joy. The chance to do interesting and difficult work.