It does help tremendously if you know your airplanes specific attitudes and power settings for various phases of flight - i.e. for the C172 I teach the most in, S&L cruise is wings level on horizon, 2400 RPM. Slow cruise and approach about 1/2 barwidth above horizon and 2200 RPMs. For ILS GS about 1800 RPM at flaps 10 and 5-8 degrees nose down. Standard rate turn a little less than 20 bank etc. Hey, even for stalls - 20 degrees pitch up power on, 10 for power off, and down to horizon for recov, and then 10 up for the go around.
Pretty obvious stuff when you yourself are instrument rated, but not obvious for the students.
I also find it alot easier to fly and to teach the control and performance technique rather than the primary and supporting technique. Also various forms of partial panel - IE start with ONLY attitude indicator and tachometer, then uncover altimeter, then heading indicator and make all maneuvers with this only. Then AS, then VSI and lastlys the TC. Then go on to cover up various combinations. I find that students then develop their own technique rather quickly. I would guess this is because the new instrument student does not know where to put their emphasis in their scan, and until basic attitude control can be mastered, everything else is just noise...