In order to make decisions efficiently and equitably, up-to-date information is required. In developing countries, with limited resources, such information should be provided by means of cost-effective methodologies, in which sampling issues are of primary importance. Different sampling strategies are currently in use. At local level with reduced populations, standard approaches prove expensive and time consuming. In this paper, we opt for simple linear piecewise approximations to calculate the sample size in terms of given precision, confidence level and population size. To support the applicability of the proposed approach by practitioners in the field, easy-to-use tables are elaborated. In terms of sampling, easy-to-follow practical guidelines for household selection and transect walk planning are also provided. The article presents six rural communities in Honduras as initial case study to illustrate the validity and applicability of the approach adopted herein for sampling design and sample size determination.