The aim of this paper is to present a short practical introduction to Raman spectroscopy for all non-specialist in chemistry and physics who are working with (marine) microplastics and nanoplastics. The continually growing polymer presence in the global ocean system constitutes a crucial interdisciplinary issue. To adequately address the problem of microplastics impact on the marine environment, its ecotoxicity, fate, sources, accumulation and weathering, one should characterise the debris found. In order to identify and describe the samples, spectroscopy techniques are crucial as they enable qualitative as well as quantitative analyses. This work provides the shortlist of good practices developed during own research, method potential and drawbacks, case studies as examples, simple explanation of primary polymer spectra. Finally, some matters on the edge and future directions are shortly mentioned. The selected proper results of measurements of diversified types of samples are provided to better illustrate the problem. Display omitted •Comprehensive review and introduction to microplastics.•Combines the biological, chemical and physical approach.•The short practical introduction to Raman spectroscopy for all non-specialist.•The manual of Raman spectroscopy of microplastics.•The numerical approach to Raman signal and future trends.