Because I work in a poolroom I get to watch a lot of pool. One thing I've noted is that while watching others play I never make a mistake either in judgment or execution. When I'm playing however, things can be quite different. Even in a friendly game with nothing at stake I do not always see everything I see when watching others, and as the importance of the match grows my vision often shrinks. Sometimes when I'm not performing well in a tournament match it almost feels as though I cannot see.
Vision, in its literal and figurative senses, is key to performance and its absence can cause disaster. In order to examine vision and its importance we shall discuss first how its shrinking manifests itself, ways to recognize that and then some tools to prevent losing vision.
Any time you leave the table for your opponent and then say, looking back at it, "why didn't I do that?" you are suffering from a loss of vision. After the shot is finished and the pressure of performing is absent it is very common for options that you did not see to reveal themselves. Whenever you have just run some balls and find yourself facing an unforeseen obstacle that prevents you from completing the rack you are playing without complete vision. A more egregious example of that phenomenon is playing perfect position for a ball that cannot be made. These are mistakes that all players, even the best, have made in the past and continue to make on occasion.
The major key to retaining vision during competition lies in tempo; usually mistakes are made in haste. It's when we start playing out of our natural tempo and begin to hurry that we neglect to see what's on the table. Often we are so pleased with an opponent's miss and eager to shoot that we simply fire in the shot in front of us only to face an impossible situation afterwards. In a game situation it is imperative when arriving at the table to take the time needed to assess the entire layout. Where are the problem balls? Can I run out? If not do I play a safety now or do I run a few balls and use that perfectly situated five ball for a devastating safety several shots from now? What is possible?
Another way to retain vision is to stay in the game while your opponent is shooting. You can assess the table and predict what may or should happen while watching the way he handles things. Why is he paying so much attention to a particular ball? Why does it appear that he cannot see the run out? What will he do with that seven ball? If you stay in the game while your opponent is shooting you will already have a lot of work completed when you get a shot. Not paying attention or letting your mind wander while you are in the chair takes you out of the game and forces you to make every necessary decision about the rack when you come to the table for your turn. Also, keeping your focus on the table and the balls helps prevent the importance of the game from taking over your mind and facilitates your ability to manage the balls instead of trying to manage the pressure.
A great way to work on vision is to watch a lot of pool and pay attention, particularly when great players are playing it. When watching others play, examine the problems that you see and make predictions for their solutions. Learn to experience what you are seeing. Often, when watching professionals you will see shots or solutions that you did not imagine. If you can experience what you see while others play, you're more likely to recall it when you find yourself in a similar situation. Try watching a match on TV with the sound off to give yourself an opportunity to make predictions without the interference of the commentator. Another huge benefit from watching professionals is apprehending the concept of many possibilities. If you watch and experience what they do you can come to the table in situations that are not similar to what you've seen just knowing that more is possible. That is a great viewpoint from which to play and invites your imagination to create solutions to the problems that you face.
Playing with vision allows us to perform. The best way to develop and nurture vision is to visualize. Visualize what will happen before taking a shot. Practice visualizing pool and its various shots when you are not playing. Visualize yourself performing consistently and effectively. Visualize yourself performing magic on the table. Great players often turn the most dire situations around by replacing a fear of failure with a willingness to amaze.