Well Maggie that all depends on how you define a community-based cafe. What is it that makes the cafe in some way different, special of relevant to said community? Does it have any specialities specific to the community it intends to serve? Is it located within a community hub, are there competitors? When all is said and done it is impractical to determine a way to market without that market (i.e. the community) being well defined and fully researched.
If you send me you location, I can provide a map of the catchment area, showing areas of about 300 dwellings with estimated discretionary income, and a complete list of all addresses for these areas.Your cafe is more likely to be successful if you can attract more regulars from your catchment area, compared with your competitors.
A key part of success will depend on the quality of your overall hospitality offer, as well as the value in special offers that you provide to the locals in your catchment area.
I've sold a niche Instagram account to an investor and she is now monetizing that account. Hope you can elaborate what you mean by community-based cafe. Is it built by or for the community?
This is an interesting concept. I would suggest you start by actually establishing and nurturing a community! Have you ever done that or is that something that you are currently doing?