The first thing you want to consider in order to increase your speed for your volleyball spiking approach is making sure you are back in a ready position to spike! I know it sounds obvious but think of this, more often than not a volleyball spike approach begin in a transition play, as a result you need to practice this skill.
There are few skills in the sport of volleyball as much fun as volleyball spiking. In this series of videos Andor Gyulai will explain what it takes to have perfect technique and form when hitting a volleyball. This series of videos on the subject are the most popular videos in the world on learning volleyball spiking and hitting technique.