A real-estate investor who's written multiple books shares 2 ways to build wealth through rentals — including one that can deliver financial independence in 15 years

David Greene doesn't believe in shortcuts in life. Whether it's in work, sports, or something else, the host of the "BiggerPockets" podcast thinks you must put in the necessary hard work to achieve what you want. But today, particularly on social media, tips for shortcuts from financial influencers …