Effective Study Techniques Guide

I'm a college student preparing for final exams in [Specify Subject, e.g., Biology]. Explain three powerful, science-backed study techniques: 1) Active Recall, 2) Spaced Repetition, and 3) The Feynman Technique. For each method, provide a clear, step-by-step guide on how I can apply it specifically to my Biology material to improve my understanding and long-term retention.