Martinich, author of the LDS Church Growth blog, has published a series of case studies on the growth of the Church of Jesus Christ of Latter-day Saints globally, including on opening new cities for missionary work in general and two case studies in Ghana and Ethiopia showing how that was done specifically. Of interest to me, he recommends leaders use cost-benefit analysis in determining where new cities should be opened as part of the "homework" required for the revelatory process.
In Sunyani, Ghana, there were previously no members of the church in late 2010 when 6 young missionaries and one senior couple were sent in to form three "groups" (very small congregations ... yes, very small) in a city of less than 100,000. In the course of one year they had not only turned two of them into "branches" (small, but self-sustaining congregations, in this case around 50 people attending each week) but a fourth congregation had also been formed. The branches are being led by local leadership instead of missionaries.
In Awasa, Ethiopia, one family had been meeting since 2003 but did not become a branch until 2008 (average attendance about 20). When full-time missionaries were assigned in mid-2010, attendance rocketed from 20 to 70 by the end of the year. There are now four congregations there, though attendance has been highly variable and most of the members appear to be under the age of 21. Some local religious leaders also joined the Church during this time period. The groups are still heavily dependent on the missionaries for leadership and training.
In other posts, Martinich reports on recent Church growth in Sierra Leone and the temporary removal of senior missionary couples from the Democratic Republic of Congo following the election violence last month.