Wow! I didn't realise people relied on the mirror so much for foot placement... thanks for the heads up!
If you're looking at becoming an instructor, I would definately use orkanbobs suggestion of working your way out of view from the mirror during a class. You're going to need to not only be confident with your own foot placement and form - but take in your participants footplacement, technique etc as well... If your busy wondering where your feet are, you could just as well be in a room without any participants at all (if you know what I mean) because your focus wouldn't be on them.....
Hmmm tricky mate - If it were me, I'd ...
1.borrow a step from the gym and practise every free moment at home til I nailed it....
2.if the gym weren't willing to loan the step I'd look at a purchase,
3.or practising on a bench at the gym as the last resort (without a mirror)....
4.Crikey, better still - borrow a DVD and do it at home - could even practise learning some choreography - even just a track, and practise not looking in the mirror (cause it's not there) or your feet and running through some chore'.....
5. set up your video cam at home and video yourself using the bench (just doing some basic moves, regardless of whether you've learnt any choreography) - then watch it back - this will let you see if you 'present' the move the same as you 'feel' the move... and from there you can correct your own technique....(much the same as the mirror aye)
Just the way I think I'd attack it, but regardless of how you choose to go about it ...
GOOD LUCK and happy stepping!!! :O)