learn to start and operate a small business - a service business, i.e. Entrepreneurship.
Check out Sweaty Startup (google his site). He has a page with a ton of service business ideas you can start and get operational and profitable in 2 months, NO DEGREE REQUIRED. The first 2 months would be learning to market your service (Facebook marketplace, Craigslist, OfferUp). Hint: Just showing up when you SAY you will show up will make you MORE competitive than most others offering the same service. Learn to charge appropriate amounts, learn to bill/invoice for work done. HINT: take photos and include that on your invoice.
After 2 months, learn how to hire an employee and put them to work. This is learning to manage people.
Once you build this base, figure out how to grow from here. See MJ's videos about getting established, then working towards decoupling your time for money.