[@Mae] A large group can be tricky, especially after about the first 20-30 posts when the stories are starting to take root and develop. 

1) Plan out in advance as much as you can
2) World Narratives can help a lot because not all characters will be around each other all the time. These help you break up how much information you are having to dump at once
3) Try to make each rpers experience unique. With large groups it is easy for one or two rpers to get left in the dark, find ways to make sure each character in the rp has something to do
4) Walk the balance between speed and slow posters. The larger the group the more diverse the posters will be. Make sure to have a minimal posts between last rule but also a must post by this day. It helps tremendously with keeping the posting momentum going without getting over whelming.
5) Chat room, private for your rpers. It's better than pm's much of the time for the exchange between many rpers during a short period of time.
6) Utilize colabs for small talk exchanges but don't let your rpers drag it out either.
7) Keep notes in a pm to yourself!

There are more of course but these are just right off the top of my head.