Crystallization
To make things clear we can use a simple example. We take a bowl of water to which we add sugar crystals. We keep adding sugar to it until we reach a stage when no more crystals can be dissolved. This solution is now a saturated one. It is interesting to note that we can dissolve more crystals to this particular saturated solution by heating it. Solubility of solutes increases with increase in temperature, but there are exceptional cases. This increase in temperature causes more sugar crystals to dissolve (so forming a supersaturated solution). When the temperature of the solution cools down, the solubility goes down, i.e. not as much sugar can be dissolved, so the extra sugar crystallizes out. This process is one of the simplest  supersaturation techniques.