  A simple classification is given of the anisotropic relativistic star models,
resembling the one of charged isotropic solutions. On the ground of this
database, and taking into account the conditions for physically realistic star
models, a method is proposed for generating all such solutions. It is based on
the energy density and the radial pressure as seeding functions. Numerous
relations between the realistic conditions are found and the need for a graphic
proof is reduced just to one pair of inequalities. This general formalism is
illustrated with an example of a class of solutions with linear equation of
state and simple energy density. It is found that the solutions depend on three
free constants and concrete examples are given. Some other popular models are
studied with the same method.
