Start a tiny business, no matter what it is. Sell stuff you make on Etsy, spend a weekend writing a tiny e-book about a topic you know well and publish it for $

Start a tiny business, no matter what it is. Sell stuff you make on Etsy, spend a weekend writing a tiny e-book about a topic you know well and publish it for $5, whatever - literally anything that requires you to define a product and then find customers for it. Bonus if the business involves creating the product (rather than buying it), but that's not required. Any experience selling something that you think solves a problem - and getting used to failing and iterating, not avoiding or worrying about that - is worthwhile.