I get asked some version of this question a lot, usually by someone standing at the start of the same road I started on. What do you wish you had known. I have thought about it enough over the years to have a real answer, so here it is.
You will not get the first deal right, and that is fine
Nobody's first property is their best property. Mine certainly was not. I did not understand yet what I was actually buying, what it would cost to hold, or what I would need to know about the tenants and the neighborhood before I signed anything. I learned those things by owning the property, not by reading about it first.
The lesson is not to avoid the mistake. The lesson is to make it small enough that it teaches you something instead of taking you out of the game. Start smaller than your ambition wants you to.
Patience is the actual skill
Everyone talks about finding the right deal like it is a matter of looking hard enough. It is really a matter of being willing to pass on nine deals to get to the tenth. Early on I wanted every deal to work, and that made me talk myself into properties that were not actually good, just available. The investors I have watched do this well over the decades are not smarter than everyone else. They are more patient than everyone else.
The deal you walk away from costs you nothing. The deal you should have walked away from can cost you years.
Know your numbers better than the person selling to you does
This one took longer to learn than it should have. If you cannot explain, in plain terms, what a property needs to earn and what it will actually cost you to own, you are not ready to buy it yet, no matter how good the story sounds. I still run the same basic math today that I wish someone had made me run at 22: real expenses, real vacancy, real capital costs, not the optimistic version.
A lot of what I learned about reading a market rather than reacting to it is the same discipline I describe in what thirty years of owning property taught me about investing here. It starts with the numbers, every time.
Relationships outlast any single deal
The contractors, the lenders, the other agents, the people who called me back on a Saturday because I had called them back on a Saturday years before. None of that shows up on a spreadsheet, and all of it mattered more over thirty years than any one transaction did. Treat every person in a deal like you will work with them again, because you probably will.
The slow version of success is still success
I did not build anything overnight, and nobody honest will tell you they did. It took one property, then a few more, then a shift in what kind of properties made sense, described in why I moved away from single-family rentals. Each step only made sense with the ones before it. If you are standing at the start of your own version of this, the unglamorous truth is that consistency over years beats intensity over months, every time I have seen it tested.
The takeaway
If I could hand my younger self one sentence, it would be this: buy less than you want to, know more than you think you need to, and give it more time than feels comfortable. Everything else gets easier after that.