For doing specific "research", I follow the method we learned from IEW (http://iew.com/shop). Have the children find 2-3 books/sources (or more) and do a short list of topics each book covers. Then, they should decide upon the number of topics they will include (or that you want them to do) for their writing assignment and pick their topics. After the topics are chosen, they create a short keyword outline for each source about that topic. Then, one topic at a time, they begin to fuse these outlines into one outline (with 4-7 ideas if creating one paragraph per topic) and begin their writing.