In recent years, the development of advanced materials has been fueled by the rapidly expanding field of study known as polymer nanocomposites. The properties of the resultant nanocomposites are significantly enhanced by the addition of nanoparticles to a polymer matrix. Dental restorations, food packaging, biosensors, electronic gadgets, and other biomedical applications are just a few of the many fields in which these advancements are essential. This chapter provides a comprehensive analysis of several methods for creating polymer-based nanocomposites, including emulsion techniques, melt intercalation, sol–gel procedures, and in situ polymerization. Furthermore, characterization of these nanocomposites is necessary to comprehend their morphology, structure, and mechanical characteristics. Techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) are frequently used to examine these characteristics. In addition to their mechanical qualities, polymer nanocomposites’ thermal characteristics are very intriguing. These thermal and chemical properties are evaluated using Fourier Transform Infrared (FTIR) Spectroscopy, Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The review’s overall goal is to provide a comprehensive understanding of how polymer nanocomposites are combined and analyzed, as well as how these procedures aid in the development and enhancement of materials for a range of industrial and medical applications.