Start from where you are: how close are you with your neighbors?
The situation can be so different it is hard to give general advice. Some places neighbours hardly talk at all. In other people know each other and cooperate on an almost daily basis. In some places there are one or two things that work – like sharing a trailer.
If people hardly know each other then you’ll need to dream up a few ways of catalysing the connection. One simple start is to greet everyone you see. One place in Italy created a Facebook group first, then they started meeting in real life.
Is there an understanding there is a climate crisis? Are people ready to do something? If not, building community by getting people to first know each other a little bit, then finding one shared activity.
A local street flea market was the way used in one Swedish town. Everyone had a stall outside their house, and people went around chatting to each other.
Or just invite people for coffee or tea in your graden or yard. Any excuse will do!
In one Swedish town local people were upset about clear-felling. People from the local nature club organsed a protest in conjunction with a demonstration day. They invited neighbours up to the clear felled woods to take a picture of them holding placards. It made the local newspaper.
So have a think about where people are in your neighbourhood and see what a good next step might be to try.(And have an idea of the next steps. You as the catalyst will need to keep the kettle boiling.)