When people try the kettlebell swing for the first time, they often lift the kettlebell and swing it with their arms and shoulders. The key is to use the hips. If your hip thrust isn’t quick or “violent” your kettlebell won’t  swing very high and you’ll find yourself struggling. You really have to pop your hips, like this guy. Check out more of his videos: http://www.youtube.com/user/rockbodyfitness?feature=watch