Perovskite materials are the focus of an enormous research effort in the field of solar cells. The outstanding intrinsic optical properties of perovskites are one of the fundamental keys to their success. Planar configuration is in particular attractive regarding the compatibility with tandem solar cells, and potential in commercialization. Despite all the breakthroughs in the field, the optical mechanisms leading to highly efficient perovskite solar cells lack profound insight. In this study, a comprehensive guideline is introduced to improve photocurrent of various types of perovskite solar cells including semi-analytical equations for thickness optimization of the front and rear transport layers, perovskite, and transparent conductive oxides to improve the antireflection and light-trapping properties. The proposed guideline is tested against experiments as well as previously published experimental and simulation results for MAPI. The provided guideline for various types of perovskites is extended to other types of perovskites such as triple cation-based ones. Additionally, the effect of roughness is discussed to account for the effect of more practical cases on the light trapping properties of perovskite solar cells. Finally, optically-optimized structures are simulated electrically.