Pin up the latest letter. Add items from newspapers about the area. At their own level of interest, different groups can produce flannelgraphs and models for children, parties and music for teenagers, political and theological issues for the more studious, etc. This helps to focus attention. You could have a special knowledgeable speaker, a link person or plan a supper with typical food and music of the country of your interest.
Theses are nearly always the most popular causes to support.
However, building projects are not always the most useful help from the overseas Church's point of view, especially if they haven't easily got money to maintain the facility. So it needs to be thought through for a long term and be appropriate for the local culture and the local budget. At some stage this is highly desirable. We often find we want to give and have to admit humbly that we receive. Prayer brings us back to the reality that mission is God's mission to be conducted in His way by His chosen instruments in His perfect timing.