This chapter suggests for readers that are not running a routine monitoring programme but need to organise fieldwork and sampling from scratch. A number of practical issues need to be considered when sampling for cyanobacteria and cyanotoxins and good preparation greatly facilitates on-site work. A protocol for on-site inspection and data collection should be established, allowing a rapid and easy entry of data that are not logged electronically. Among the hydrophysical conditions affecting cyanobacterial occurrence, the most important ones are turbidity, temperature profiles, pH, oxygen concentration and – for rivers or streams – flow rate. Turbidity reduction is associated with particle removal, including cyanobacterial cells, and is generally a valuable operational monitoring parameter for the efficacy of filtration methods. Good logistical preparation prior to fieldwork requires that equipment is checked to ensure that it is functioning properly, for example, regular testing and calibration of electrodes; testing and changing of batteries; and keeping operation, maintenance and calibration records, respectively.