I like to draw a line down the hill and have the student make parallel turns across the line and have them touch the pole on the line with their downhill pole, then turn after the pole is in the correct position with the tip of the pole pointing behind them.
I also do follow the leader, where they follow in my tracks and do their pole touch in the same spot as me and then turn in my tracks.
One of my favorites, that I use to get the student to feel their center of mass cross over their skis at turn initiation is to have them take their poles off and hold them vertically with their hands spaced hip width apart. Then as they traverse across the hill, have them poke the poles in the direction of their new turn, (so laterally, across their body and downhill, just poking at the air, not down into the snow) and them move them back to their position. The turn will happen almost automatically when they do this.
I also demonstrate that the pole touch is done in more of a lateral movement toward the new turn, and not at the tip of their ski. Doing the pole touch in a more lateral movements, opens the hips and helps get your COM moving toward the new turn much quicker.
Hope these help!