you can add more solvent or heat up the solution if the solubility of the solute increases with temperature.
What you can also do (although not completely a physical process) is add stabilizers in the solution. These stabilizers are somewhat specific to the solute and solvent combination. Such compounds are used extensively in the food industry and you might find some names as ingredients in a lot of food products.
Let me take an example of how they work in case of inorganic salts. You might have heard of the silver nitrate test for chlorides.
Now what happens is silver chloride has a very very low solubility and hence forms a concentrated solution at a very low concentration of silver chloride. Anything excess (which is normal quantity) and the excess comes out of the solution as a white powder (if you want to know about common ion effect let me know). Now if we add ammonia solution to this, the ammonia forms a complex with the silver ions and basically does not allow much silver to remain in the solution. This is lower than the concentration needed for saturation (in other words, it is an unsaturated solution) and we now get a clear solution. And voila, we have a stabilizer for silver.
There are similar stabilizers available for different types of compounds. Although, don't try to use ammonia as a food stabilizer :) .