CFIs are the #1 "Aviation Influencers!" What you say, do, and teach will determine the future of aviation.
This is a tough test that encompasses all that you have been taught until now. First, examine *your* skills and knowlege and compare/sync w/FAA Handbook Guidance. Everything must conform to the FAA guidance!
Preparation = CONFIDENCE/SUCCESS! You will impress your FAA Pilot Examiner!
Your best overview for the flight portion of any flight evaluation is to be meticulous and methodical (the conservative response rule). As a Commercial-level pilot, be a PRO, responsible for passengers. Smooth, coordinated flight (anticipating not reacting). Use your checklist "religiously" for every operation and if you are not sure about anything ASK. This is not a time to be a hero or try to impress your examiner by cutting corners or being fast. Discussing "checklist philosophy" ("do list" vs "checklist") during your oral is important.
In flight remember that limitations mostly 10 degrees/100 feet) are like the lines on a highway. Going over the line is undesirable but not necessarily an immediate failure (the examiner will clearly state if/when you failed). "Failure to promptly correct" is what the ACS defines as failure. Demonstrate to the DPE you are aware of any deviations and fixing them promptly (remember "perfection is not the standard"). If you are "consistently exceeding standards" you will probably be disapproved ("more training!") Exceeding any aircraft limitation (flap speed is common) is an immediate failure so give yourself a margine on these. Know all your performance speeds and the bold faced checklist items (immediate action items) should be memorized.