There are two general types of methods for preparing miniemulsions:
* High-energy methods - For the high-energy methods, the shearing proceeds usually via exposure to high power ultrasound of the mixture or with a high-pressure homogenizer, which are high-shearing processes. 
* Low-energy methods - For the low-energy methods, the water-in-oil emulsion is usually prepared and then transformed into an oil-in-water miniemulsion by changing either composition or temperature. The water-in-oil emulsion is diluted dropwise with water to an inversion point or gradually cooled to a phase inversion temperature. The emulsion inversion point and phase inversion temperature cause a significant decrease in the interfacial tension between two liquids, thereby generating very tiny oil droplets dispersed in the water.
Miniemulsions are kinetically stable but thermodynamically unstable. Oil and water are incompatible in nature, and the interface between them is not favored. Therefore, given a sufficient amount of time, the oil and water in miniemulsions separate again. Various mechanisms such as gravitational  separation, flocculation, coalescence, and Ostwald ripening result in instability. In an ideal miniemulsion system, coalescence and Ostwald ripening are suppressed thanks to the presence of the surfactant and co-surfactant. With the addition of surfactants, stable droplets are then obtained, which have typically a size between 50 and 500 nm.