CFI-I practical
The CFI-I flight is basically an instrument ride from the right seat. You have to execute all procedures while "teaching" them. An important caveat is your teaching methods must follow the FAA's line in every way. Take it from someone who knows.
The FAA's position is always the final word on what to know, why it's done, and especially how to do it. Item: Go read up on attitude instrument flying in the Instrument Flying Handbook. Know primary and supporting inside out and forward and backwards. While control-performance with emphasis on the AI may be how it's really done and how Alitalia might teach instrument flying, control-performance gets scant mention in the Handbook and is heresy to the FAA. Actually, primary-and-supporting helps control-performance because it helps you understand what you need to do to get the airplane to perform the way you want.
A vital thing to know is how to analyze why a student's parameters are always off. Learn and understand the common errors of instrument cross-check (Yeah, I know it's "scan," but the FAA says it's "cross-check."). I.e., emphasis, omission, fixation, etc.
Teaching BAI is a bit of a sales job. You have to sell your students that the AI is a substitute for outside references. You demonstrate outside references for a particular flight regime and show how and where they appear on the panel. You will also have various pitch and power settings for constant-airspeed climbs and decents, rate climbs and decents, cruise, and holding. You could create a table of these settings for your airplane and have your students memorize them. Then try them, in the airplane and/or sim. The airplane becomes predictable. Someone said that when one becomes an instrument pilot he/she is no longer a test pilot.
One final point. Be sure to teach your students to tune and identify navaids. The obvious safety issues notwithstanding, not doing so is a bust. Same for not keeping the ADF volume up when working with NDBs.
If you have taken your instrument practical relatively recently you should do fine after a thorough review and drill by your instructor. Also, be prepared to answer some FOI questions. Although you have demonstrated that you can teach and know the fundamentals of instructing, plenty of examiners still grill add-on applicants on the FOI.
Hope these points help. Good luck with your rating.