That is a pretty meaty passage of Scripture! Is there anything in particular you plan to focus on -- a theme or a smaller number of verses? I see the ideas of sacrifice, grace, spiritual gifts, and love as ideas you could choose to focus on. Depending on the age group you are working with, you wouldn't want to do too much at once.
Love - some of these ideas on the Great Commandment might work.
Verse 14 talks about blessing those who persecute you, and other ideas that are similar to the Sermon on the Mount.
Let us know a bit more about what your goals are for Romans 12 and we can try to give you more ideas!