A lot would depend on what you mean by "keeping it going", and a lot will depend on what practical requirements the small church has.
If it has a full-time pastor and a premises to maintain that obviously requires financial resources that a small church will increasingly struggle to provide. Perhaps there's scope to cut back on some costs there to buy some time.
Ultimately the church needs to either draw more members in, or contract/split into groups small enough to meet in someone's home.
Drawing more members in may be the best solution, in which case it's worth paying some attention to what "church" looks like, how new people are treated, whether issues people raise are well handled etc. As far as new people are concerned a key thing to consider is what the place looks like through their eyes - whether they are made to feel welcome or whether their presence seems like an intrusion into a closed group.
I'd recommend reading the book Scrappy Church by Thom S Rainer. Buy it from a local Christian bookshop if you can, rather than the well known online retailer. It looks at a lot of stuff about how churches can inadvertently push people away. From what I recall (it's been a few years since I read it) the author's focus is on the experience of people looking for a new church rather than people looking to see if there's anything to our faith, but it's also worth considering how church comes across to the unchurched. I've often wondered how people who are thinking there must be more to life and whether this guy Jesus they've heard about is relevant to them, would react to a church service. Many church services are filled with man-made routines that the regulars know well but newcomers may find quite offputting, and sometimes a congregation can appear very judgmental towards those who don't fit in with what's expected.
It's very easy for an established congregation to get into the mindset that "everybody knows this", and the chances are that everybody does know it. Everybody, that is, except for the people who need to know it. The visitor, who potentially leaves their first service feeling like the odd one out who nobody showed any interest in talking to. The seeker, who was left so bewildered by the routines that everybody except them knew that they leave with the conclusion that church isn't for people like them. If we're lucky they'll try another church; if we're not maybe their next stop is a mosque or a temple, or maybe they'll just go back to a strip club or something.
As one who is currently looking for a new church I've seen quite a difference in how churches react to new people. Sometimes you'd be forgiven for thinking their long-lost child had returned home. Other times you'd be forgiven for thinking nobody even noticed we were there. One key point made in Scrappy Church is that if the only time anyone talks to the new person is during the "greeting time" (a hideous invention if ever there was one) then you might as well regard them as not having been greeted at all. Because nothing says "you're not welcome" quite like the fake smile and handshake prompted by the leader saying "and now greet your neighbors", followed by being ignored for the rest of your visit.
From an insider's perspective take a look at the church and see whether it looks like a church or something more like a social club. It's easy to get into the idea that what we do in church is obviously, well, church but look at how many unwritten and unspoken rules people are expected to follow. Is there a dress code, however informally defined? Are people expected to act in a certain way, think a certain way, follow certain protocols? It's one thing to expect basic Christ-like standards in church but if a new person comes in wearing jeans while everybody else is wearing a three-piece suit they will probably feel unwelcome. If the congregation makes their disapproval of something evident, when the something is unrelated to Christian living, they drive people away. It often seems that the people churches are most likely to shun because they represent a bad look are the ones Jesus hung out with when he walked this earth as a man. How would the church react to someone who showed up wearing ripped jeans, or someone with very visible tattoos, or similar?
Sometimes it only takes one or two people to make someone feel unwelcome - I personally know someone who abandoned their church because of some particularly cutting remarks made to them by a very small group. On the face of it someone might say it was trivial but it was enough to make that person feel like they didn't belong in that church, or potentially in any church. Some months after the fact they still aren't attending any church. I left my former church six months ago and only recently started exploring other churches in the area because I had no interest in dealing with the garbage that so often comes with church. Looking at that specific part of my own "church walk" it's easy to see why someone less established in their faith would just walk away completely.
