For the beginner

Another thing that I really like for a beginner is just trading in one stock at a time.  In my belief diversification is just a way of admitting that you really have no idea where anything is going at any time.  By trading one stock at a time you have the chance to think about your trade, see how it acts and make a decision to keep it or not.  Someday trade two or more but for now just one and you will lose less money (in my opinion) 

Slow down and think about your trades

I have learned many things in the stock market but one thing I know is that a calm patient mind makes the most money.  Or at least if I lose money I am not in a panic state that usually confuses me and causes me to lose more because all I want is my "Money back".