“You are good at this” can sound like appreciation and still leave somebody feeling unable to decline. When asking a neighbour to help, make the size of the request as clear as the compliment.
Name the task, its likely duration and the support available. “Could you show two people how to fold the display stands on Saturday, with me beside you?” gives someone more to decide on than “Can you help with the event?”
Leave a genuine route to say no. A person should not need to disclose work, health or family circumstances to explain why an apparently small task is too much this week. Avoid asking in front of a group if that would make declining awkward.
Separate this request from the next one
If somebody agrees to one session, record that scope. Do not silently turn their help into ownership of the equipment or a standing duty. Ask again when the task changes, even if they did it well the first time.
For example, a volunteer might agree to demonstrate a craft but not to buy supplies, collect payments or answer messages afterwards. Those are separate responsibilities with different demands.
When the job is complete, acknowledge the agreed contribution and release the person from it. A useful closing message can say what was done and who will handle the remaining work.
This makes future invitations easier to trust. People can participate in a manageable piece of community life without having to guess what extra responsibilities will arrive after they say yes.
Image: a thematic illustration, not a photograph of this example.