The key to successful management of an emergency situation, and/or preventing a non-normal situation from progressing into a true emergency, is a thorough familiarity with, and adherence to, the procedures developed by the airplane manufacturer and contained in the FAA-approved Airplane Flight Manual and/or Pilot's Operating Handbook (AFM/POH).
AIM Ch. 6 Emergency Procedures
AFH Ch. 17 Emergency Procedures
91.3 Responsibility and authority of the pilot in command
Cessna SOPM 1-96 Section 1-4: Emergency Procedures
Private Pilot ACS Page 50 IX. Emergency Operations