The activity is a personal service activity in which you materially participated for any 3 (whether or not consecutive) preceding tax years. An activity is a personal service activity if it involves the performance of personal services in the fields of health (including veterinary services), law, engineering, architecture, accounting, actuarial science, performing arts, consulting, or any other trade or business in which capital isn’t a material income-producing factor.
We have 1 rental at the moment and we are renovating the second one. Last year we generated over $14,000 net passive income (after mortgage payments and taxes) from one apartment, and all I had to do was go in to inspect the property 3 times to make sure the tenants weren’t destroying it! It turned out they kept it in perfect condition and they were lovely people! Call me lucky.

Vanguard: Vanguard has a minimum of $50,000 and a fee of 0.3%. Rebalancing is done automatically once every quarter and tax loss harvesting is done on a client-by-client basis. We included Vanguard because clients who invest between $50,000-$500,000 have access to a team of financial advisors. Those with accounts over $500,000 will have a dedicated advisor.

If you can save a lot early on in life, you can build up sources of unearned income, and this income will be exempt from payroll taxes. This is good news for investors and for retirees. Any pre-tax salary deferral contribution made to a retirement account, pension plan, or other pre-tax contribution will lower the amount of federal and state income tax liabilities, however, they do not lower your payroll/FICA tax - the FICA tax has already been taken out of gross wages. 
I have only dabbled in drop-shipping before when I had an eCommerce platform 6 years ago or so. I think it is something that you could do on the side, but you would want to do in depth research on the industry you want to get into before setting up shop. It may be a little less passive up front, but over time you could take your hands off the wheel.