The uses of nanoparticles had garnered more interest because of their variety of applications in the fields of physics, chemistry, biology, pharmacy, and material science attributed to creating new nanocomposites which have unique properties used in particular applications. Now, these properties of nanocomposites are affected by a wide number of parameters relating to the microstructure due to the embedding of the nanoparticle inside the polymeric matrices. The present work is to understand the new trends and developments for polymer and/or polymer blend incorporated nanoparticles with the following strategies: i) the methods and techniques for dispersion of nanoparticles, and ii) the influence for a good dispersion on the properties of the nanocomposites. We discuss the different methods to prepare the novel nanocomposites with discussing in details the variation of techniques to analyse these nanocomposites such as X-ray, SEM and TEM with study the thermal, electrical, and magnetic properties. Enhanced dispersion of nanomaterials in the polymeric matrices may be extending the developments and applications of the nanocomposite. In addition, this state of the art work is focused on different kinds of nanocomposites: i) new trends to preparation and processing methods, ii) study of newest results on structural and properties and iii) wide applications of nanocomposites as a novel material. Current or future applications of these nanocomposites are highlighted.