I have gotten a lot of advice from many different sources about our upcoming trip to Ethiopia, so unfortunately I cannot properly credit these. But the two most useful pieces of advice so far have been:
1 - Find a guide / interpreter from the same ethnic group as your child.
The more I learn about the history and culture of the Burjii, the more I realize how important this is. The Burjii are a very small ethnic group who have been scattered across countries, languages and religions. Despite their differences, the overriding commonality is that they are Burjii, and they seemingly will do anything to help one of their own. There is a level of trust there that I think would not be afforded to an outsider.
2 - Just going counts as a success.
We may want to learn more about our children's history, grow their identity, feel more connected to their family, bridge some cultural barriers... but if none of these things happen, it is OK. If we can just physically get ourselves to their homeland, that counts as succeeding... This is the advice I come back to every day. It is a wisdom that keeps me sane and grateful for the amazing opportunity we have.