Don,

In my experience with technos, the biggest factors are:

- people can't see as well, and dances are often more crowded, so stuff with higher collision potential are out. Orbits, pousettes, star promenadrs ... Caution!
- you draw a slightly different demographic, often newer dancers, so the overall difficulty is lower and you're calling longer
- people get lost easier with less lighting, louder music, music whose phrasing may not be as clear, and the trancey nature of it. Again, calling longer.
- Matching balances can be a lot easier or harder, greatly varying on the songs.

Good luck and have fun!

Ron Blechner