“How to be a brilliant investor” is not an idea suitable for a newsletter, because the newsletter would be only one email long.  The email would say: buy a couple of indexes, take the right amount of risk for your circumstances, and keep your costs low. That’s it. If a person were to do all that, they’d likely do as well as a dedicated professional investor: around seven per cent per year before tax, subject to risk appetite. Such is the power of efficient markets.  Happily for newsletter writers, people don’t do the three things. They make mistakes. Over and…