I recently invested a five digit sum and it turned out to be one of the worst deals I ever made. I'm not a classical investor or VC and currently I don't have a lot of money to invest, but I really want to learn how investors/VCs think and act. This would help to avoid investing hard-earned money in junk projects and also to learn how great business opportunities can be identified, whether that is in the startup scene or in other avenues. I want to learn the metrics of investing into businesses and how to separate "wheat from chaff". I realize this platform is more for helping entrepreneurs, but apparently there are some people in here who are both, i.e. entrepreneurs and investors. So what is the best way to learn the art of investing in businesses? How do you become an investor? How do investors spot and analyze business opportunities? Any tips? Any books or websites out there?