Success is measured in many different ways. A fundraiser may measure success by how much money was raised. A conference or teaching event may measure success by how much people learned. There is no single way to determine success because it depends on the purpose and desired outcome of the event.
Consider the Daniel Boone Days Booth. What was the goal? Perhaps it was for us as a congregation to work together and foster our zeal for evangelism. Maybe it was to make the Church known in the community, to make good impressions, or to share the Gospel with others. If those were the goals, then the booth was successful.
Now, think about Friends and Family Day. Was it successful? Again, we must consider the purpose. Maybe the goal was simply to invite someone to services, open the door for a conversation, or bring people to hear the Gospel, and see how to worship God. If those things were accomplished, then it too was successful.
Spreading the Gospel is not always meant with instant responses. Not everyone we read of in Acts responded to what was taught. However, the Church still persevered and continued in spreading the Word and grew. We never know who we effected this past weekend in our efforts, but we must be diligent in spreading His word and pray that those around us will respond; meaning that we must be those who continue looking for others who are lost and looking for the truth.