It's a bit of a Catch 22: You can only get enough by discovering you already have it.
Those who chase money or fame will never have enough.
It's not about money or stuff. In fact, everyone you know has too many things, and would actually be happier owning fewer things. Recycle, give away, donate or trash three things today. It'll feel liberating. Do it again tomorrow.
Stay off the hedonic treadmill. Things you want are wonderful, when you get them they turn into things you have, and you don't get to want them anymore.
Kurt Vonnegut, in his 93-word poem "Joe Heller" articulated it clearly, observing that a billionare could have made more money yesterday than Joseph Heller's novel "Catch 22" ever did. Joe's response:
Beyond that, find something bigger than you that matters and contribute your energy to it.
Even if your goal is happiness, trying to be happy for your own sake isn't likely to succeed. You are far more likely to achieve happiness as a byproduct of working towards something you find meaningful, even if you never achieve it, than you will by making happiness the goal.
Know that you have enough.
Know that you matter.
You can pour yourself into something meaningful, and you can be happy.
That's something you can be thankful for.