The only time it’s appropriate to say the name of “That Scottish Play” (( I won’t even say it at all, or type it, even when I’m not in a theatre. )) is when you’re referring to the character Lady MacBeth.
It’s French custom to say “Merthe” to one another before a performance. ((We all know what that word means.)) And screech is right. Never ever ever wish someone “Good luck”. Not even the stage crew. Always say “Bad Luck” or “Break a leg”.
Trust me.
As for warm-ups. These are “VERY” basic, but first thing’s first. Your voice:
PuhTuhKuhs
Pick a point on a wall about ten feet away and focus your sound on that spot. Repeat the consonant sounds of P, T, and K “PUHTUHKUH” over and over again while gradually getting louder and softer. Pay attention to where your toungue is while you’re doing this and get a feel for how your mouth moves. At the softer points, your sound should just reach that wall, and at the louder points it should pierce through it.
Ya-Yo
May want to do this one with a group. The purpose of the exercise is to open up the back of your throat. Make “Ya” and “Yo” sounds with varying pitch and loudness ((not so much that you strain your voice… stay in a comfortable range)) and focus on making the inside of your mouth and the back of your throat as big as possible. Even if your lips are close together.
Now you want to work on the body:
Stretching Routine
If you exercise at all, you probably have a stretching routine that you feel really comfortable with. If not, you can find one in any fitness book or video. I’m sure someone’s got something you can borrow. Just find something that’s comfortable and not strenuous. Do this first, and at least an hour before showtime.
Loosey Goosey and the Duck Walk
This is one I taught the little kids and they loved it. It works really really well for loosening up and getting comfortable with your cast mates. Again, try to get a group of people to do this. ((It would look pretty silly otherwise.)) You’ll feel much more comfortable with each other afterwards. It goes like this, whomever the Loosey Gooseys are move around with arms and legs as wide as possible and flop and flap. However, if you touch someone else or a wall you have to Duck Walk for a count of ten. The Duck Walk consists of making yourself as small as possible, tucking everything in and getting as low to the ground as you can while still being able to walk. That’s pretty much it. You can also quack and honk, but I think that’s mostly a kid thing. 
Anyway, that’s a few things to do for warm-ups. As far as memorizing lines. One thing that I’ve found works really well is everyone sitting randomly in a circle and saying their lines in order as fast as possible. If you do it correctly, you should be stepping on cues left and right. It also works for adding a little energy to the performance, and it’s definitely good for a laugh.
To any extent, I hope I’ve helped. Break a leg! 