This depends on the type of mixture.
There are several different ways and procedures of separating mixtures, though, some mixtures areirreversible, and can permanently be combined. A few ways of separating mixtures is through evaporation, filtration, sieving, gravity separation, distillation, condensation, froth flotation, magnetic separation, chromatography, and centrifuging (http://www.slideshare.net/brittgow/separating-mixtures-1247457). Also certain chemical reactions can separate mixtures, or create substances, i.e. acid+base=salt+water etc. (If this is no help I'm sorry just look up separating mixtures on Google).
by separating it
Examples are: evaporation, extraction electrophoresis, elutriation.
Using the separating funnel method can be separated mixtures of liquids with different densities.
evaporation and filtering
oil and water
Filtration is the best method.
It is called distillation
DISTILLATION
Separating mixtures can help to reduce waste by allowing components to be reused or recycled. This reduces the amount of material that ends up in landfills or in the environment. Additionally, separating mixtures can help to prevent contamination of soil, water, and air by harmful substances.
The easiest way to check is if there is a difference in colours between parts of the mixtures.
the main way of separating a solution is evaporation or distillation, to separate two liquids this doesn't work. someone improve my answer.