The biggest challenge is preserving the income for special uses. Some of the funds must be used in a way that enables the congregation to see the results. Projects should be visible in church structure, programs and local missions. Make the campaign a long-term priority of the church. Repeat the invitation to give to the endowment fund.
Communication is one of the foundations of every stewardship program.
Here's a story that illustrates my point. Just think of the stewardship message this sends. The church only contacts you if the information is negative. Forget that most statements can be hand delivered after church, or that people appreciate being kept informed about their pledges as the church asks them to keep pledges current. If we want people to respond to the church's stewardship message, we must remain faithful to it as well, including communication about what the church does with the resources people entrust to it and the status of pledge payments.