To help the Pentecostal Missionary Church (denomination) of Tanzania raise a steady steam of support for the work of the church in evangelism and church planting, and also to help the various pastors and ministry people get some means of support. If businesses could be started up that would hire many of the needy church members that would be super!
Entrepreneurs and those who have tried a variety of fund-raising projects would come and do what they do best. Size up the situation, and brainstorm, and then involve others in carrying these ideas out. It would be important to avoid “get rich quick” schemes and half-baked ideas. Set up fund-raisers that will work, and train others to repeat them.
Entrepreneurs and those who have expertise and ideas for fund-raising that would work in Tanzania, or in a world-wide/internet way. Take into account that Tanzanians for the most part have little discretionary money, The funds will most likely have to come in from the outside. The people are creative types so producing craft items to sell online is a possibility, while a big concert with ticket sales is not.
Too many at once would create confusion, but generally one or two at first, and then more as new opportunities are created.
Think long range for this kind of work. You might be able to start a fund-raising plan or two, and train some Tanzanians to run with it in just a few weeks, but ideally, you should plan to stick around for a year or so to follow through and show that your ideas really work and produce funds for the PMC church denomination, and others.
Depending on the fund-raiser's requirements, help to find an apartment or home to rent when they arrive, and show them around to introduce them to the people they are to help. Then basically be available to answer questions and brainstorm as they look for the most suitable ideas to carry out.
Once the fund-raiser has come to know and understand the people and the situation, it might even be possible if it is necessary for the fund-raiser to leave and to continue the oversight of the plans via the internet. But that should be discouraged and only used if the personal presence way cannot be continued.