This is the trader’s ability to attend to the smallest details of his or her trading plan.  I believe a trader must have rules for entering and exiting a trade before the trade is made.  In the beginning these rules can be in the form of a checklist wherein before each trade all the details of your rules are checked and verified.  With time, the rules become such as a part of your psyche that the checklist is in your head and can be confirmed with quick precision.  The key is to never change the rules. When the rules stay the same your mind will not be able to play tricks on you.