Mine is writing.
Yours could be painting or dancing or making coffee or doing yoga or building computers or creating font or mixing music or planting trees.
Do it everyday. Not just to establish 10,000 hours. Not just to be ready for failure. Not just to work out exactly how it will produce down the line.
Do it because you have to. Your daily whatever is the thing that holds you together as a person. You bleed your art, and when you’re done for the day, it displays your bloody fingerprints.
My advice is to not worry about its monetary or cultural worth yet– if you do it as yourself, it is enough.