  The discussion of enhancement of superconductivity is presented in the
framework of the higher-grade hybrid model of layered superconductors. The
enhancement is considered from the following two points of view: (i) as a
result of long-range couplings with respects to the short distance ones, and
(ii) the enhancement of 3D superconductivity with respect to the 2D.
  Two important cases are distinguished: homogeneous bulk supercoducting
materials and superconducting structures composed of a finite number of layers.
