You must have a stock market mission statement before you begin trading.
A lack of a proper mission statement will lead to all sorts of problems.
A typical stock market mission statement will include the following points.

• I will not time the market Do not ever attempt to do this because it is impossible.
  There is no wayto buy at the lowest and sell at the highest points.
  There will always besomething lower or something else higher.
  You simply cannot tell, so makeit your mission statement never to time the market.
  Go with the flow anddo your best.
  

• I will not be stubborn The stock market is a moving and an unpredictable thing.
  It is alwayschanging and never stays any one way .
  So it is important for you to stayflexible.
  Do not become stubborn over some stock or the market itself.
  Traders often hold on to useless stock for several years even when allevidence shows that the industry sector is dead or showing negativegrowth.
  Cut your losses and get rid of that stock.
  Stubbornness is not agood attitude when trading in the stock market.
  

• I will pay my taxes Profits are good and they are the first reason you are trading in thestock market.
  Play the game for it is worth and make all the money thatyou can.
  Do not regret having sold a stock too early if you made profit.
  The market will give you another chance soon.
  Paying taxes is as importantas making profits.
  You will sleep better and enjoy your profits bettertoo.
  

• I will think for myself The stock market often displays humans following the herd mentality.
  Onetrader or a small group might panic or be over excited about some stockand pretty soon the entire market will be swaying towards that.
  Do nottrust "hot tips" just because they sound good.
  Research allfacts carefully and decide the merit of the tip before deciding to actingon it.
  Always think for yourself and never follow the herd.
  

• I will not get emotional Of all the oddest things to happen, sometimes traders will fall in lovewith stock.
  Or they will simply hate a company for some reason.
  The thingis that these emotions have no place in this business.
  Do not follow youremotions but follow good trading techniques.
  

• I will only trade in the best Study the market and follow the best companies.
  You will see that over aspan of time, these companies have given substantial gains to all tradersand investors.
  There are many duds out there and you will have to do a bitof sifting.
  Once you are done, you know for sure that you will never tradein anything but the best.
  

• I will check my expectations The stock market is also subject gravity.
  It might go unbelievably highbut it has to come down eventually, even if it for just a short distance.
  Do not indulge in unrealistic thoughts about how the market will not comedown any time soon.
  

This is a rough outline for your stock market mission statement.