It's all about Connection:

A healthy growing small group requires dynamic relationship connectivity.  People can be led to become involved in one another's lives.  Connection requires trust.  Trust is built up over time.  New people need to feel connected at a beginning level the first time they experience the group, and they need to be able to observe that deeper connections exist in the group so they have that to look forward to should they choose to plug in.  I recommend, and this is a real key, that every member and every prospect must have a connection contact every week.  That means some type of interaction needs to take place each and every week.  Either they receive that on Sunday morning when they are present, or if they are absent, they get it in some other form.  Some of those forms are: a phone call, an email exchange, going to coffee, personal visit, a card or letter, etc.  If you want to maintain personal connectivity in a healthy way, no person should be able to miss without a caring response from the group that cares for them.  This is critical!  In addition, regular fellowship and activity times really help to build relationships.  Home bible studies, ice cream fellowships, going out to eat together, dinners for six, and on and on give opportunities to build connections outside of the weekly meeting time.  I recommend at least monthly activities of some type.

A healthy growing small group requires transforming biblical connectivity.  People can be led to interact with the Word of God in a transformational way.  The "lesson" must be excellently prepared, thought provoking, and challenging.  It is a sin to bore people with the Word of God.  It is a dynamic, life changing book, and it must be presented as such.  I always say that no learner should be able to walk away from an encounter with God's Word the same as they arrived.  It is the job of the guide or learning leader to make sure they challenge themselves and their students in at least one of three areas:

If our thinking, behavior, or our priorities do not line up with the teaching of the Bible, guess who needs to change!

A healthy growing small group requires prayer connectivity.  Prayer is a powerful force for binding a group together.  I always recommend that prayer be a priority.  Prayer partners, prayer chains, prayer circles, all help the group to be a part of one another's lives.

A healthy growing small group is connected by ministry to one another and ministry outside the walls of the church.  Meeting the needs of the group when they arise is essential to making the group feel like a family.  Births, deaths, hospital stays, birthdays, anniversaries, job loss, and on and on are all opportunities to minister.  In addition, every group needs to incorporate and outward focus as well.  Ministry projects like mission trips, feeding the homeless, working the soup kitchen, helping the elderly, and on and on can be a wonderful addition to any small group.

So, that's just off the top of my head, hope this is what you were looking for!