They persevered by devoting themselves to:
1. listening to, learning from, being with, and emulating the Witnesses;
2. breaking real bread together in agape, and sharing Living Bread together in communion; and
3. praying together.
Think of it - the Apostle Witnesses were right there with them. If the Apostles played Kevin Bacon, they were just one degree separated from Christ! They were the Patient Zeros from which the Movement of the Way would spread across the globe. Is it any wonder that First Church lived in AWE (not just awe, but AWE)? How does one respond to AWE via living?
"All who relied upon Christ were together and had all things in common." Srsly?
How do you do "together"? They first cut their anchors, exorcized their demons, and threw off the chains of their idols by selling their real-estate, their inheritances, their stuff. Then, they pooled together the proceeds of the sales. The scripture does not say that the money was divided up according to merit or importance. It does not say that it was divvied up equally or "fairly". We are told that it was distributed according to need, justly.
This freed them. It allowed them the time and opportunity to worship together daily. They were able to eat together in agape fellowship with "glad and generous hearts" because they were free of the fear of scarcity and no longer possessed by evil spirits of possession. They praised God continuously, and demonstrated his goodness by doing good to all.
All? They were not of the world, seeking only to benefit themselves or their own comfort. They were not separate from the world, avoiding temptation, living in fear. They were in the world, working to make it better. All!
They are not said to have advertised, marketed, or otherwise solicited. Nor is it written that they developed programs, fun activities, or had entertaining services. They did not do anything we think we have to do to attain church growth. They did not do anything, but visibly love God and love others by their actions. They did not have to tell people over and over again how good they were; people saw them being good and doing good - and day by day Luke tells us, God added to their number.
Some say that they were communists. Some say it was easy for them to surrender their need for things because they thought the world would end any day. The Earth did not end, but the world as they knew it did. Generation upon generation we have learned the mystery of faith: we are all still just one degree separated from Christ, we are the Witnesses. The Kingdom will fully come maybe, when we all realize that there is zero degree of separation. Maybe, someday?