How a librarian would approach this assignment:
1. Identify your U.N. Peacekeeping Operation location (first link)
2. Read through the U.N. information on your operation (fact sheets, "UN documents" on the bottom of each Operation page)
3. Read the "Effectiveness of Peacekeeping Operations" article for context
4. Search for additional sources on the effectiveness of your operation by searching for the name of it in OneSearch; also try SIRS Researcher and perhaps CQ Researcher (all linked below)
5. Draft it out and look for additional sources if needed