Unsure of how old this was first posted, but, being a person who has had several decent groups [Hopefully;;]. Would like to say my thoughts on what a grand leader would be.
For me I would say interaction is BEST. My old group BV [Broken Vengeance] and SP [Scarred Paws] was quite big and had some of the larger packs talking until I got a little stressed out over small things and went on a hiatus, etc. But, I made sure to make sure members not online had updates on our site, activity, making sure being active was fun and appealing, the role-play wasn't so boring. Talking out some big decisions with my members, allies, enemies, etc.
Another good quality would be your dedication and kindness. I myself, is little too kind.. like, you can be kind for a good relationship with your members but, don't let anyone stress you out or stomp on your group. You must be able to be respectful, kind, polite but, also be able to clear possible rumors of your group, keep any misbehaving members in order, or else you might get a bad reputation if that misbehaving members causes something big and, big drama = no fun for everybody.
Going alongside with A LOT of the people above, is to just overall be respectful and make sure you listen to what your members are saying, take into consideration ideas, let them help out in development, make sure you all are having fun with what your doing.
Soon you'll have a happy group that's having fun getting on to chat, play games, have fun and, role-play. This'll influence your role-play A LOT. People won't be the usual, 'sitting in the background, sigh' type of deal. You'll all be excited to meet one another, actually contribute and act as a family in the role-play. This will also make people more keen to join your group by just watching the role-play. All of this just from basic good, interaction merely OOC. Making friends with your members I have to say is KEY, for a successful group.
Like really, name one group that hates their members that's active and has lasted for over a month with occasional role-play.
Hope this helped!
Also if you'd like, here's a few screenies of my two groups I named above. ^^
Scarred Paws [SP]:
Broken Vengeance [BV]: