Decomposition through thermolysis, electrolysis, photolysis
You should analyse the chemical bindings in your compound, e.g. ion bindings will easily break-up in water, stronger bindings may require You to use heating or electric current to dissociate the molecule. Also if you know the structure of the compound, look for some similar structures on the internet, the more similar the structures, the more similar properties they have, so similar factors will dissociate them.