I'm not very experienced, but I've done a couple of vids in different venues.
Tactics depends on the venue. if it's arena sized, get a seat at the rear dead centre if possible, you can probably put the camera on your thigh (reduces shaking), set up using LCD, and just check occassionally, cover with coat/jumper. If you get brave or have the opportunity you can try a bit more zooming, but generally just get the stage in the shot and leave it be.
If the venue is small and you're on the balcony, well it's much more difficult and the same method don't really work, as you'll need to get the camera as high as possible to get a shot through heads/shoulders (risky, as I know from experience). In which case you'll be better off on the front row (I did play around with putting cam in a sweaty armpit with a hole in a shirt, but never put it into practice)
It really depends on the venue and the position, just be flexible, obviously a tripod/minipod will improve the recording but I would expect they are tricky to set up (but still possible) and give a lack of flexibiity.