Abstract: In this paper, we summary the thermoelectric history, background, applications and the approaches to enhance the thermoelectric performance. Several approaches to enhance ZT have emerged in the last decade, such as modifying the band structure and band convergence to enhance Seebeck coefficients, nanostructuring and all-scale hierarchical architecturing to reduce the lattice thermal conductivity, aligning band energy between nano-precipitate/matrix to maintain hole mobility. Alternatively, one can seek high performance in pristine thermoelectric materials with intrinsically low thermal conductivity, which is a promising method to find potential thermoelectric materials. Finally, a discussion of future possible strategies is proposed to aim at further enhancing the thermoelectric figure of merit of thermoelectric materials.