Mostly I use MMario's technique but when I actually prepare I warm up in the car en route. I start by singing something that requires some expression but that consists mostly of lower tones. Then I'll also make some relaxed sounds that sound like a cross between clearing my throat and the Awesome Voice of Tibetan monks. This seems to release the tension that prevents tone production. Finally, I'll work up to songs with some higher notes and end by trying to make that high train whistle sound where two falsetto notes are made at the same time. I'm not very good at making the train whistle sound but I've discovered that the excersice of trying to make it (only for a very short period of time) helps get that end of the voice working; well, working as well as it's going to anyway.

Bill Monroe always stayed away from alcohol and sucked on half a lemon before going on stage.

      - Mark