The Daily Trading Game Plan is what we use to excute the strategy set out in the Trading Plan. To illustrate what we mean, let's say that the Trading Plan calls for a buy at next day's open whenever the 20-day SMA crosses the 50-day SMA, then the Daily Trading Game Plan would contain a list of stocks where that condition has been met - it gives the green light for the trade to be filled the next day at open.
The Daily Trading Game Plan should be prepared the evening before for the next day, when the market is closed and you have time to think calmly. By all means go ahead and prepare it in the morning before the market opens if you're an early riser, but give yourself time to think. Depending on your trading strategy, you may also visit the game plan during the lunch hour, to see whether any new stocks meet your trading criteria.
Trading can be a stressful business, but it's very much easier when you have a plan to help keep you focused. Without a Daily Trading Game Plan, it's possible to fall prey to boredom or a rush of blood to the head, and end up buying stocks on impulse. If you make it your rule to never act unless the stock is on your game plan you may miss some winners but overall you'll come out ahead.