There are many ways to separate the mixtures and it can be done on the basis of the type of the mixtures.
The principle used in the separation of a mixture employs a special property of one of the components of the mixture. e.g. the heterogeneous mixtures are separated by Hand-picking, sedimentation, Decantation, Filtration, etc.
if the substance is a lightweight we use winnowing. if the substance is in large shape we use sieving and if the substance is liquid we use evaporation.
For example, iron pieces mixed with sand can be separated using a magnet as iron gets attracted towards the magnet.