One of the most appealing options, particularly for millennials, would be #12 on your list (create a Blog/Youtube channel). The videos can be about anything that interests you, from your daily makeup routine (with affiliate links to the products you use), recipes (what you eat each day) or as you mention, instructional videos (again with affiliate links to the products you use). Once you gain a large following and viewership, you can earn via Adsense on YouTube.
As doctors, we most likely fall into the first category. We may be rich in the sense that our salaries are in the higher economic range, however, because of our expenses (houses, cars, student loan debt, private school tuition, practice overhead, etc.) and sometimes poor decisions, we have a tough time accumulating any real wealth. We’re also handicapped by the fact that we start along this financial journey relatively later in life.
1. The batting cage idea is very risky. I’ve seen many of them close over the years and it is not anything close to passive income if you want to keep the business going. You have to continually promote it and target youth leagues, coaches, schools etc to catch all of the new players who grow up and want to play. I’ve played at probably 8 batting cages over the years and 7 of them closed.
Dividends made sense 40 years ago as a relatively simple rule of thumb, but after all the work done by John Bogle with index investing, and academics with Monte Carlo sims and the 4% rule, dividend investing just isn’t the simplest, cleanest way to invest or receive passive income anymore. It’s actually significantly more risky compared to index investing, because dividend companies are a much smaller share of the total global economy compared to the broader indices.
If you're looking to get started in real estate, look at a crowd funding solution like RealtyMogul. It works similar to LendingClub - you commit as little as $5,000 towards a property. When the property is fully funded, you become an owner, and will receive your share of the earnings and appreciation in the property. Check out RealtyMogul to learn more.