A well-built clinical question follows the PICO format.
P = Patient/Population: Describe the most important characteristics of the patient or population
I = Intervention: Describe the intervention (e.g. drug or treatment, diagnostic test, etc.)
C = Comparison: Describe the main alternative being considered (e.g. placebo, the gold standard, etc.)
O = Outcome: Describe what you're trying to measure, accomplish, improve, or affect