I try to get to the SDC classes as often as I can too, they are such fun, I usually stay on for another class! I love jazz and contempo, but I haven't done classical for awhile...
HSC has been pretty bad on my dancing though, I wish I could do it more often! I keep in shape mainly because I'm naturally quite thin and also because I watch what I eat pretty well. With technique, since I don't get to practise that much, when I go for walks or runs I always do stretches and practise positions for about 10-15 mins and always, always stretch, +c @ home - its just so comforting and relaxing.
I used to go to the gym, but time and money does get tight during yr 12, so I quit that about two months ago.
Anyway, I guess I try to fit what I can, when I can to help with the HSC and everything else.