A general approach to describing a number of phenomena in strongly correlated electronic systems is examined. These phenomena are united by the fluctuation nature of the effects and the presence (or appearance) of nonuniform charge and/or spin densities. The following problems are discussed: the nature of ferromagnetism in d metals; the reasons for the appearance of metallic conductivity in oxides of heavy p metals; and, the nature of the pseudogap state in high-temperature superconductors.