Study more being a landlord and the importance of agreements and especially sec 8.

This includes meeting with the city, engineering, conducting required studies, plat maps, etc.

I would study the different real estate investing techniques that you could comfortably afford to get into and find the one that interests you the most and go for it.

HiI have been studying the Poland real estate market and it looks quite promising.

Would you use that type of in depth study?

If you want to make the opposite case, look at engineering degrees or point to the wage studies that show on average people with 4 year degrees make a lot more than those who have zero college.  

I don't have the time to study Bitcoin nor do I have the time or desire to study any individual company thus I invest my traditional retirement savings into low cost index funds.That being said, I do feel like I can study and become educated about my local residential real estate market and it is an interesting topic to me so that is where I spend my time, effort, and excess capital.Regarding, investment vs gambling. 

There have been at least 3 studies that show this is true for virtually every large city in the US (you can internet search this).- buy and hold is currently tough in San Diego.  

@Allan Smith We've seen SFH properties with a purchase price as low as $150,000 benefit from a cost segregation study.

Start studying comps and understand what is a good or bad deal and why.