Curious what procedures you guys are teaching for getting slowed down for the approach and when to dirty things up. I am more interested in something a little higher performance than a 172 (more like a bonanza), but really looking for the procedure you use and the why behind that method.
Are you getting the gear down early in the procedure to slow you down, or waiting until the FAF? What speeds are you teaching them to fly and on which segments of the approach, and if you are having them stay fast, why?
You are probably already thinking in terms of the common pitch-power-performance configuration charts that identify a number of phases of flight and give you the numbers, so I'll start there (if you're not, do not pass GO; do not collect $200).
The phases (people will use more or less) generally include level pre-FAF /GSI level flight, precision and non-precision descents, level flight at the MDA (for non precision approaches), and missed approach.
One issue you'll come across with higher performance airplanes is a common disagreement about final approach speeds. For example, I flew a Comanche single for a while and there was an ongoing disagreement about whether to fly approaches at 120 kts or at the 90-100 kts that the airplane's approach category would suggest.
Your decision about that may affect some of the other considerations. This may sound a bit disjointed, but give you some idea of the thought process I use:
I prefer the 100-kt approach on the final approach segment. OTOH, I don't really want to slow down to that directly from cruise. So, in higher performance retracts, I add a "vectoring" configuration to the mix. When leaving the enroute to the approach environment in, say, that Comanche, typically during the descent, I would bring the MP back gradually to a target setting that would give me 120 kts when leveling off. That would allow me to get to a speed that was close enough to my final target for the approach, but still take advantage of the airplane's higher speed capability.
Getting closer to the FAR/GSI, I'd slow down again, this time to my target approach speed. The goal is to be at my 100 kt target at level flight for the final approach segment comfortable before reaching the FAF/GSI.
Then crossing the FAF or intercepting the glideslope, it's a simple matter of putting the gear down to go down.
As shdw noted, sometimes you can't do what you want. But I found that my "vectoring" configuration had another advantage in that it was also my "keep your speed up configuration." That 120 in level flight translated to 120 on the final approach segment by simply putting the gear down.
Like I said, that gives you something of the thought process I use and teach. But there is a variety of different techniques all of which will produce acceptable results. I think the key to it all is to (a) know what settings will produce certain results and (b) know where
in the process to apply those techniques to get a smooth transition while staying ahead of the airplane.