How can i convince people to donate money to help me pay a vet bill?

well an alternative is too go to the media with that story depending on the animal a news station would eat that stuff up and you would probably get the money through someone seeing it or the news station itself, depends tho if the news is slow that day. but to get people to know its for the surgery i bet you could talk with the doctor and ask the shelter to take the donations for you...i think they might refer you to some charity system they already have though instead.