The study of cellular diversity has become increasingly critical in various fields of biology, including genomics, single-cell analysis, immunology, and cancer research. Cell clustering methods play a pivotal role in understanding and characterizing this diversity, enabling the identification of distinct cell populations within complex tissues and heterogeneous samples. This comprehensive guide aims to provide an overview of various cell clustering techniques, offering researchers a roadmap to navigate the intricacies of cellular heterogeneity analysis. In this guide, we begin by outlining the importance of cell clustering in elucidating cellular heterogeneity and its implications for biological research. We then discuss the foundational principles behind cell clustering methods, covering the broad spectrum of techniques, including traditional clustering algorithms, dimensionality reduction methods, and machine learning approaches. The guide delves into the practical aspects of data preprocessing, feature selection, and quality control, all of which are crucial steps before embarking on cell clustering. We also examine the specific challenges and considerations when dealing with single-cell RNA-sequencing data, which has emerged as a cornerstone technology in the study of cellular diversity. Throughout the guide, we emphasize the importance of selecting appropriate clustering methods based on the research objectives, data characteristics, and biological context. We discuss various validation strategies and visualization tools to assess the quality and interpretability of clustering results.