Define the study objective
Identify the target population
Choose the study design
Select the primary outcome variable
Set the desired confidence level
Set the acceptable margin of error
Estimate the expected effect size
Estimate the population proportion or mean
Determine the statistical power
Choose the significance level
Account for variability in the data
Use the appropriate sample size formula
Apply finite population correction if needed
Adjust for expected nonresponse or dropout
Round up to the nearest whole number
Verify the result with a sample size calculator or statistician