Single-cell RNA sequencing (scRNA-seq) is a revolutionary tool for studying the physiology of normal and pathologically altered tissues. This approach provides information about the molecular features (gene expression, mutations, chromatin accessibility, etc.) of cells, opens up the possibility to analyze cell differentiation trajectories/phylogeny and cell-cell interactions and allows discovering new cell types and previously unexplored processes. From a clinical point of view, scRNA-seq allows a deeper and more detailed analysis of the molecular mechanisms of various diseases and serves as the basis for the development of new preventive, diagnostic and therapeutic solutions. This review describes the different approaches to analysis of scRNA-seq data, reviews the strengths and weaknesses of bioinformatic tools, provides recommendations and examples of their successful use and suggests potential directions for improvement. It also emphasizes the need to create new, including multi-omics, protocols for the preparation of DNA/RNA libraries of single cells in order to obtain a more complete and systematic understanding of each cell.