Instructions
Find a safe and secure location to snipe. If you eliminate the blind spots that are behind or to the sides of you, you will have less of a chance of being seen or killed from the back or sides. Since your sniper scope encompasses only a small view, it is important to find a good vantage point where you can oversee the entire map.
Press and hold the R3 button, which is the right joystick button on your PS3 controller. Holding the R3 button will perform a breath-hold, which will help stabilize your sniper rifle to get a more accurate shot.
Aim for the center of body instead of the head. Although head shots are impressive and deliver an instant kill for all weapons, you do not need a head shot for a one-shot kill with a sniper rifle. Since sniper rifles have almost a maximum attack strength, any shot to the body will also kill the opponent. The body is a larger target and you are more likely to hit the body than the small head target.