Neck strikes are very effective and they don't require much finesse to execute. In the video below there is an example of a neck strike from the
rear--that is to say that the attacker struck his target from behind. The result was an immediate knock out. This type of strike is very dangerous and potentially lethal. Better used in a fight for your life or the life of a loved one rather than in a contentious social situation.
When practicing with a partner, move slowly and deliberately so that you get the targeting right--every time. And for the sake of your training partner as he/she will experience a whip lash effect when you step through them. Things to remember include: stepping through (or past) your target; use the forearm and don't collapse it when you execute; front leg bends; back leg straight; back foot flat on the ground so as not to lose your balance.