Acts 2:42–47 
42 All the believers devoted themselves to the apostles’ teaching, and to fellowship, and to sharing in meals (including the Lord’s Supper), and to prayer. 43 A deep sense of awe came over them all, and the apostles performed many miraculous signs and wonders. 44 And all the believers met together in one place and shared everything they had. 45 They sold their property and possessions and shared the money with those in need. 46 They worshiped together at the Temple each day, met in homes for the Lord’s Supper, and shared their meals with great joy and generosity—47 all the while praising God and enjoying the goodwill of all the people. And each day the Lord added to their fellowship those who were being saved. 

1. A healthy small group is marked by biblical teaching.
42 All the believers devoted themselves to the apostles’ teaching 

2. A healthy small group is marked by prayer.
“And they devoted themselves . . .  to prayer.”

3. A healthy small group is marked by fellowship.
“And they devoted themselves . . . to fellowship.”

4. A healthy small group is marked by generosity.
45 They sold their property and possessions and shared the money with those in need

5. A healthy small group is marked by consistency.
“They worshiped together at the Temple each day
6. A healthy small group is marked by gladness.
“and shared their meals with great joy

7. A healthy small group is marked by praise.
all the while praising God and enjoying the goodwill of all the people
“God wants your praise not because he won’t be fully God until he gets it, but because you won’t be fully glad until you give it.” – John Piper

8. A healthy small group is marked by growth.
“And each day the Lord added to their fellowship those who were being saved

 

For more: 

https://www.9marks.org/article/using-small-groups-cultivate-fellowship/

https://www.gospelrelevance.com/2015/08/24/9-marks-of-a-healthy-small-group/