High energy conversion efficiency is one of the most important keys to the commercialization of dye-sensitized solar cells (DSCs) in the huge electricity generation market. According to our experience in the persistent efforts that helped to achieve high efficiency DSCs, we selectively review the major progress of improving the energy conversion efficiency of DSCs which may be useful for future applications. We start the discussion from modelling the device by macroscopic equivalent circuit and then highlight some approaches to improve the device performance, such as the molecular engineering of novel dye sensitizers and light trapping effect, tuning the potential of redox shuttles and surface passivation of photoelectrodes, and optimizing the resistance. Finally, we illustrate a roadmap of possible future directions of DSCs with the challenges of how to further improve the efficiency to accelerate the progress in the commercialization of DSCs.