Defensive linemen learn to react to the movement of the ball and the movement of the offensive player. An offensive player must learn to move on a sound and to anticipate the reaction of the defensive player. Not moving the instant the ball is snapped almost always will result in an offensive lineman losing the battle to the defense. So the first thing offensive lineman must master is firing off the ball to initiate a successful block.
Once the snap count is called out you should instantly move forward out of your stance and fire out. When coming out of your stance remain low with your head up. Remember to take quick steps, keeping his feet close to the ground.
Both arms should fire out and fit into the defender while keeping your shoulders low and square with your back straight. You should also keep your neck bowed and head up. Each lineman should have his eyes focused straight ahead, looking at an imaginary target.