Great question @Brett G. and I think a really important one to start with when first looking at real estate investing.
What do I want my life to look like once my real estate investing business is up and running?
The life of a successful house flipper is very different from a successful note investor.
The life of a successful buy and hold investor in single family homes is different from a successful commercial real estate syndicator specializes in large multifamily.
Every one of the above strategies has the potential to provide you an amazing life and build enormous wealth. However, they are very different and I think it's really important to begin with the end in mind.
Most people here are looking to generate passive income. I prefer to call it risidual income. It takes work to generate that risidual/income, but it keeps paying you long after you put in most of the work. Notice I said MOST of the work. Most of these strategies still require some work to keep them functioning correctly. How passive they are depends on a lot of factors; buying right, doing business with reliable people (good tenants, property managers, contractors, etc.), building and perfecting systems that work with minimal input from you.
I've seen buy and hold landlords struggle to maintain two properties "passively". I've seen landlords manage an enormous portfolio of single family homes very passively. I'm in awe of people like @J. Martin who have built portfolios of short term rentals (NOT the most passive investment strategy) that continue to function and put off cash flow even when he's vacation down in Columbia for over a month. In his case, it's about systems, systems, systems.