Poor aqueous solubility of some drug molecules is a major problem in drug formulation. Drug nanosuspensions emerged as one solution to delivering such hydrophobic drugs. Scaling down to nanoparticles enhances drug aqueous solubility and bioavailability by increasing drug surface area that comes into contact with biological media. Nanosuspensions that have attracted particular attention are those sterically stabilised by steric polymers such as polyethylene glycol (PEG) with a typical size range of 10-100 nm. These nanoparticles are capable of accumulating in targeted areas such as cancer tissues and infarct zones with minimal damage to healthy tissues. Nanosuspensions are often prepared by commercially available methods such as high pressure homogenization, media milling, emulsification, and melt emulsification. Solidification and surface modification methods are post-processing techniques used to add particular properties for advanced therapies. In this review, we firstly describe preparation methods for nanosuspensions. Secondly, we highlight typical characterization techniques. Finally, we describe several practical application of applications for drug delivery design and different administration routes such as parenteral, pulmonary, oral, and ocular.