Quick related question...

I'm going to be joining a friend for a few gigs around St. Paddy's Day this year. Up until now, my singing is usually limited to a few songs in sessions, usually two nights a week maximum.

For these gigs, however, I'll be singing a greater number of songs, and for longer periods of time, over four consecutive days...culminating in two gigs on the holiday itself.

We will have a PA system, so I'll be able to conserve a bit more than normal, but any recommendations (other than what's listed above) on things I can do either
1) to prepare my voice in advance for that weekend, or
2) to preserve it during that weekend.

Afterall, I don't want sound like Lou Rawls by Monday night's performance.