Tip-enhanced Raman scattering (TERS) is one of the few methods to access the molecular composition and structure of surfaces with extreme lateral and depth resolution, down to the nanometre scale and beyond. This Primer examines the underlying physical principles driving signal enhancement and lateral resolution of TERS, laying the foundation for both theoretical understanding and practical applications. Addressing critical factors such as reproducibility, averaging and general limitations, we delve into the nuances of TERS experiments. Various TERS modifcations are introduced, highlighting diverse optical geometries and tip feedback schemes tailored to the specifc experimental needs. State-of-the-art TERS studies are showcased to illustrate its versatility, encompassing structural analysis of biomolecules, nanoscale investigation of chemical reactivity and exploration of the intrinsic physical properties of 2D materials. These TERS applications serve as a comprehensive overview of current advancements in the feld, encapsulating the breadth of TERS experiments.