The following article was written by Larry Albach, aka Bladerunner (SASS Life #1538) - 
a long-time, successful, meticulous shooter.

MARKSMANSHIP FUNDAMENTALS

MENTAL DISCIPLINE

     Analyze what you are trying to accomplish in your shooting program, then plan a direct, positive approach to your desires, such as: physical conditioning, mental preparation, dry firing, trigger control, sight picture, breathing and relaxing.  Before shooting, imagine the sights in your mind.  Close your eyes and try to keep the sights aligned in your mind's eye.  Imagine the shots going off and the positive way you are reacting to the rhythm of your shot string.  Imagine your perfect recovery and preparation for the next shot.

     Conditions such as wind, rain, heat, dust, and cold can adversely affect your shooting.  Whatever the adversity, it affects every shooter on the line to the same extent, ignore them!  Let everyone else gripe, moan and complain about the conditions.  But you concentrate on the job at hand.  Make each shot your best shot.  Be sure you and your equipment are ready for the job at hand, shooting match-winning scores.

     It is extremely useful and important to match winning scores.  Proper breaching relaxes the body, calms the mind and lowers the pulse rate.  All these points are extremely important.  Within three to ten seconds after breathing deeply, the pulse rate lowers and this is the best time to start the string of fire.  Whenever there is a break on the firing line, use this time to your advantage by breathing deeply.  Never let a slow down in the course of fire rattle you.  Welcome it, use it to your advantage by breathing deeply and relaxing, letting the tensions drain from your body.

     The proper stance is the one that puts you in the proper alignment with the target so that you are in a comfortable position and not relying on your muscles for support.  Use the bonds and ligaments of your body to support you - not your muscles!  When you use muscles, they take oxygen, then the heart beats faster, causing a faster pulse, which gives you a larger arc of movement.  Your guns come up pointing naturally to the center on the target.  If not, shift the position of your feet right or left to bring the line of sight to the center of the target.

     There is a natural "arc of movement" when your arm is extended, which is impossible to eliminate it.  But this can be minimized by a lot of diligent practice on your part.  By strengthening your arms, you can decrease this movement to a point that is barely noticeable.  The important thing to realize is this exists and to work with it and not against it.  By proper breathing and trigger squeeze, you can get off your shots when the arc is at its minimum.  Never make the mistake of snatching an X, or jerking the trigger when the sights are in perfect alignment, you only succeed in throwing the shots off.

     The grip on the gun should be a good, firm, solid grasping of the weapon, with equal pressure on both sides of the weapon.  This grip should be the same always, or a change of impact points will occur.  The placement of the trigger finger should be the same each time, with the trigger centered on the center of the pad of your trigger finger.  The proper grip must become automatic when drawing by the weapon so that no shifting of the weapon is done while bringing the weapon into firing position.  Don't grip the gun so tightly that you shake, but tight enough that the recoil is transmitted to the shoulder.

     A very important point in squeezing the trigger is that you use a steadily mashing pressure.  Think the trigger back in a straight line so that when the shot goes off it is a surprise.  Never anticipate a shot.  Let them all break as a surprise.  Remember: align the sights, settle into your normal aiming area and exert positive, uninterrupted, constantly increasing pressure, straight to the rear until the hammer falls.

     It is very important that enough shots be fired in practice so that you can establish a rhythm in firing a string of shots.  Recovery after each shot is of primary importance so that the sights are aligned as fast as possible for each succeeding shot.  Take all the time allowed for each string, as it's to your advantage.  Watch the front sight always during recovery so that it is in alignment for the next shot.

     Follow through is simply the immediate recovery of the weapon after each shot is fired, so that you are in the same exact position for each succeeding shot.  This means the sights are in perfect alignment, the eye is focused on the front sight, the grip on the weapon has not varied, but remains the same.  All conditions should remain the same for each shot.

     After the firing of each shot, you should be able to call the placement of each shot.  If not, then you are not concentrating on your front sight.

     Overeating causes the heart to beat faster, opens up the arc of movement.  Eat a small meal before a match.  Coffee is a stimulant and causes the heart to beat faster.  Smoking causes a faster heart beat, one cigarette after breakfast speeds the heart up for half a day.  Alcohol slows the reactions and coordination is impaired.  Colas contain caffeine and speed up the heart beat.

But the most important fundament of shooting is:

(Thanks Bladerunner. Some of us can use all the help we can get.)