HT Games
Instructions
If you're going to play on a computer, purchase a high-sensitivity mouse. The quicker and more accurate your mouse is, the faster you will be able to react and perform a headshot. Look for high-end gaming models that have multiple buttons you can bind commands to; this will also help for quickly switching weapons and other equipment.
Choose weapons you are comfortable with. Avoid ACOG scopes that cause a swaying motion--this makes performing headshots more difficult. Experiment with recoil, some guns will recoil up and will actually increase your chances of getting a headshot if your primarily aim for your target's body. The sniper rifle is fairly accurate and is also effective for headshots, but it also can leave you exposed in many situations.
Practice headshots every time you game. Practice aiming at the head at every angle when attacking a player. Over time you will get used to aiming for the other players' heads instead of their bodies. Play one or two games during a gaming session where you only aim for other players' heads. After that try playing a couple of normal games but still prioritizing headshots.
Sneak up behind the enemy for a better chance of a headshot. Take the time to aim; don't become "trigger-happy" and miss. This will just cause the player to turn around and kill you. Equip a weapon with a silencer and if possible use a UAV jammer to hide your approach; these strategies can also help you take out additional players if necessary.
Use perks that will help you obtain head shots such as "Steady Aim" and "Stopping Power." Try mixing different perks together to see what works best with your weapon load out.
Go after players below your skill level. This may increase your chance of repeat headshots if you are just trying to get unlocked items and achievements from headshots.