Hi Melanie,
I wouldn't consider myself a "sage" as I've only been investing for about six years and been actively engaged with BP for that same amount of time.
However, if considered for a "lessons learned" column, I would definitely speak to the biggest lesson I've ever learned in investing, "don't wait to buy real estate, buy real estate and wait."
I laugh at my 2016-2017 self thinking I was "buying the top" of the market and deeply regret past hesitancies! I would love to visit my old self and give myself the confidence that everything will work out and to pull the trigger on several more opportunities that were presented to me that I passed by. I let small issues like not knowing how to get a business license or properly create a lease stop me at times.
Though I am doing well now with a portfolio of six properties, I believe I could have double that had I been able to give my old self more confidence that everything will work out and to just buy more real estate!