The aim of this paper is to overview some achievements on light enhancement in photonic nanostructures. Results from litterature and from own research are presented. In recent years, a number of photonic nanostructures have been proposed to enhance light in low-index materials based on external reflections provided by interference effects at a high-index contrast interface. Since interference is involved, these structures are strongly wavelength dependent. Plasmonic devices have attracted increasing attention in recent years due to their ability to confine light below the diffraction limit, thereby potentially enabling device miniaturization at the nanoscale. Several types of plasmonic waveguides have been proposed and investigated in the literature with the aim of achieving tighter light enhancement and longer propagation lengths.