All good ideas, but 10 and 12 struck home with me. One thing we need to realise is that sometimes people can't make it and you'll have a very small group – don't take it personally (as I usually do and get all concerned). More importantly (point 12) respect the time of your members. Don't overdo it, and make sure you don't have them hanging around wasting time.
I have now taken to starting on time as much as possible, but having pizza half way through – this also helps with catering since you can order the pizza based on how many have turned up.
(via Daniel Moth, who found out about it from someone else, etc, etc)