Not a CM, but a couple of tips, some of which were already covered:
1) Don't be cattle (MOOOO!) - this is a broader tip than watch for the short line at the CS restaurant (though that's part of it). It means don't just follow the people in front of you. A lot of times, there are other line options besides the closest one. A good example of this is at the ticket booth's in the AM. Often, they will open up extra lanes right before the park opens, if you keep your eyes peeled, you can skip over to these right when the CM show up.
2) In most theatre shows, don't be in a hurry to get into the theatres, especially on crowded days. When you enter, you are supposed to move all the way to the end of your row. If you wait and let some people through first, you can get a more central seat.
3) Know where the typical character meet-n-greet locations are, and then as you are walking around, watch for "handlers" in those spots with no characters. If you see one, go up and chat and see if the characters are coming out soon...it's a good way to catch a character with little wait.
4) Be kind to CM - The people that work at Disney (for the most part) don't do it just for money. They, like many of us, love being able to spread the magic. But about 80 % of their job is dealing with people yelling or complaining. Be part of the 20 %, let them know you appreciate the work they do. Chat about what you like about the park, how their day is going. Thank them at the end of the conversation. Most of the time, you won't get anything but a nice feeling, but what's wrong with that?
5) When you do have a complaint, don't be loud or agressive...be calm even when you are annoyed. There is nothing wrong with being persistant if a problem isn't being resolved satisfactorly, but there's no need to be an a$$. Disney prides itself on customer service, and while you might not get exactly what you want, they will do their best to help you out.
SkierPete