One of my absolute favorite books to use in my classroom is Margaret Wise Brown's The Important Book. It is such a great way to get your students to think about main idea and details.
For those of you who haven't heard of this awesome book, it is a short, simple story that takes the reader on a journey through every day objects, describing them for their many attributes, but boiling them down to one main "important" thing.
Using this book as a jumping off point, I have had my upper grade students think about whatever subject it is we are studying and write their own "Important Book" pages. Most recently, we did this for our family holiday cards.
After reading the book aloud, we each Circle Mapped (brainstormed) the important things about our own families. Then, I had the students decide which one of those things was the most important. That became the first sentence of the page.
"The most important thing about my family is that they love me and I love them."
Then, I gave the students a form to follow. They filled in the blank spaces with the other things about their family they brainstormed in the Circle Maps.
The last sentence of the "Important Book" page they were writing was identical to the first.
I love this activity because it really makes the students think about what is most important about what we are learning. In this case, their family, it was a little easier because the subject was a personal to each child. When we learn about reference books, or the Oregon Trail, or fractions, it gets a bit trickier. However it really is a great way to get the students to narrow down their thinking.