Aqueous zinc-ion batteries (AZIBs) are an appealing battery system due to their low cost, intrinsic safety, and environmental-friendliness, while their application is plagued by the obstacles from the cathode, electrolyte, and zinc anode. Summarizing the design principles and strategies toward the optimization of cathode, electrolyte, and zinc anode is crucial for the development of AZIBs. Herein, we present a comprehensive analysis of the design principles and promising strategies toward the improvement of AZIBs. Firstly, the various reaction mechanisms are summarized and the existing issues associated with the cathode, electrolyte, and zinc anode are discussed to guide the rational design of AZIBs. Subsequently, we provide an in-depth and comprehensive discussion on the design principles and strategies for the electrodes/electrolyte/separator optimization, and analyze the advantages and disadvantages of various strategies. Importantly, the design principles and strategies of the newly appeared conversion-type AZIBs, such as Zn-S battery and Zn-Se battery, are also discussed and analyzed. The effect of design strategies on the electrochemical performance and the relationship between the current issues and strategies are also unveiled in detail. Finally, some research trends and perspectives are provided for designing better AZIBs.