Before you can collect data, you have to decide on the parameters of your data collection, including the sample size and composition, as well as the sampling method.
Sample Composition: The source from which data will be gathered, e.g. residents of a particular community or the general public, retailers, parks, beaches, public buildings or spaces, restaurants, multi-unit housing complexes, etc.
Sample Size: The number of units to be sampled, from which data will be collected. Serves as the denominator in quantitative data analysis.
Sampling Method: The method by which the sampling units are selected (such as census, simple random, stratified random, cluster, purposive, convenience).