In the last two decades much effort has been made to prepare thin films of organic materials using several methods. One of them is the Langmuir-Blodgett technique whose main advantage is the order control of molecules in each layer and the possibility of transferring the desired number of ordered layers onto solid substrates. In this paper we review the influence of several factors on the film characteristics. We will focus our attention on the following topics: spreading time, temperature, presence of ions in the subphase, nature, and concentration of these ions, pH, and sweeping speed. We will see how these factors influence the stability of Langmuir films, their homogeneity, the transference ratio onto solid substrates, and properties of Langmuir-Blodgett films.