I think the best advice I can give anyone is to learn the difference between happiness and joy. Most may think this is not good advice because they think happiness and joy are the same, but they are not.

Happiness is an emotion, joy is a state of being. Happiness relies on externalities, what makes us happy are those things outside of our self that trigger the emotion that we call happiness. Because happiness relies on things other than ourselves, our happiness and unhappiness is outside of our control.

How is it then that some people who are in situations most would consider unhappy such as poverty, starvation, or war, seem happy? It might be that what it is needed for them to be happy is much different than yourself, or what you think you see as happiness is really joy. People in joy choose to see the world differently, to practice gratitude (another choice) for what they have and for who they are, than to be unhappy for want.

Joy is a state of being.

Joy is what comes to mind when I read this blog post by Joan Westenberg that asks this question:

Imagine your 80-year-old self looking back at the day you’re having right now. What would they give to inhabit your body again, to have your knees that don’t ache, your schedule that seems so overwhelmingly full, your problems that feel so urgent?

Joan goes on the write:

We have pretty good data on what actually happens to people’s subjective wellbeing as they age. The U-shaped curve of happiness is one of the most robust findings in social science: people report being happiest in their twenties, hit a low point somewhere in their forties or fifties, and then happiness increases again in later life. The interpretation of this finding is contested - are older people actually happier or just better at regulating their emotions? Do they compare themselves to worse alternatives or have they genuinely figured something out?

And continues:

Does this mean the thought experiment is useless? Not quite. Its value is in what it reveals about your current priorities. When you imagine an elderly version of yourself looking back, you’re running a sort of values clarification exercise. You’re asking which parts of your current life would seem precious from a distance, which anxieties would seem trivial, which opportunities would seem worth taking.

I commend the entire post for your reading. I also recommend The Book of Joy by the Dalai Lama and Desmond Tutu.