DO set a start and stop time (and stick to it like stink on a skunk)! At your very first meeting, enter the room, greet everyone, and say, “Guys, I’m going to have to go to another meeting in two hours (or whatever). Can we go ahead and get started with item x? By the way, if I’m ever late, don’t wait on me. No reason to waste your time for me. Please go ahead and start, and I’ll catch up when I get here.” Then jump right in and get to work.
The trick is to do this at the very first meeting while everyone is still trying to figure out who’s gonna be head honcho. Speak first, speak confidently, and sound like you know what you’re doing. Most people will be glad that someone has a plan. It will also show you as someone who respects their time and will get across the idea that it’s rude to expect others to wait for them when they’re late.
By the by, a firm stop time is every bit as important as a firm start time. It puts time pressure on the group (that means less futzing around). If you start on time every time, whether everyone is there or not, it helps in several ways. Slow pokes will either learn to come on time or they will be relegated to a less-influential position (where they can do less harm). It also establishes the seriousness of the group. Classes start on time; parties start when everyone shows up.
(more to come)