1. To determine a sample population, identify the overall population to study, the sampling frame, acceptable margin of error, and desired reliability. 2. Consider the size of the population to determine whether to use a probability or non-probability sampling procedure. Formulas like Slovin's or Calmorin's may be needed. 3. Multistage sampling divides a large population into stages, such as first sampling clusters then sampling individuals, to make the sampling process more practical for a very large population.