For my OD, the above are the most important. I run a once a week OD. I kept it small this year with 6 members and we get through 2 games a week even though I said that we'd play at least once a week. I made sure to find players who were like me, I have two very young children so finding time to play is tough. My league is made up of people who have a family, full time work or go to school full time. The idea is to make sure you get people not only the same skill level as you but have the same amount of time to play as you. In my experience, some players with more time to play than me get anxious to advance while players who aren't dedicated/don't have time to play have not lasted in my OD.
And lastly, make sure you at least message your members every time you advance. Keep them up to date with what your doing in the OD as far as advancing, settings, ect. The worst thing to do is to make a change or advance without them knowing. Communication is huge especially if you have one guy left who needs to play. Only advance if you clearly stated a deadline for advancing, i.e., the OD will advance every Thursday night at 9 PM Pacific Time.
Hope this helps.