Use this instead of a Venn Diagram! Students can write the two topics in the upper left-hand and upper right-hand boxes. In the "How Alike?" box, they can compare the similarities between the two topics. In the "How Different?" box, they can contrast the differences between the two topics. The middle column titled "with regards to..." makes the students be specific when listing differences. When reading a story, I usually have the class contrast the setting, characters, etc... so that's what they write in that "with regards to..." column! Enjoy!