Based on a previously modified version of Bruggerman's method, a dependence of the effective diffusion coefficient in porous media on the porosity is deduced and compared with available experimental data. Based on the same method, a dependency of the effective elastic coefficients of composite materials on the volume fraction of inclusions is deduced in the case of different types of inclusions. Comparison with available experimental data shows good agreement between the theory predictions and the experimental data. In the case of the elastic properties of laminated composite materials, application of the same method yields results identical to those obtained using the averaging procedure. A theory of effective viscosity of concentrated suspensions is applied for calculations of dependency of effective viscosity on applied shear rate using available experimental data.