  In this paper, we present new techniques for solving a large variety of
partial differential equations. The proposed method reduces the PDEs to first
order differential equations known as classical equations such as Bernoulli,
Ricatti and Abel equations. The main idea is based on implementing new
techniques by combining variations of parameters with characteristic methods to
obtain many new and general exact solutions. In each class of PDE's, we give
illustrated examples. Moreover, the method presented in this paper can be
easily extended to classes of second order nonlinear PDEs.
