How do you determine between someone who is a typical retail investor versus an enthusiastic amateur or a professional? Just look at the underlying reasons for buying their investments.
Teaching someone to become a good investor is as large a task as training them to become a great sales professional. There are thousands, if not millions of books written about each subject and every day there are more things to learn. Most of all, it is not a crystal clear subject with definitive right or wrongs such as perhaps what you would find with accounting or in medicine. Investing, like sales, is filled with numerous opinions and strategies that seem sound, however it would be tough to prove whether they definitively work or not.