Here is my suggestion. I taught on the armor of God and it was an 8-week study! The reason it was 8 weeks is because we dove into the nitty-gritty details of what exactly we faced and what were each of the pieces of the armor. You do not have to do as I, but if you want to? I got most of my material from Ray Stedman.
http://www.pbc.org/dp/stedman/battle/index.html look up the 10 messages from Ephesians and if you don’t want to teach in detail on these subjects, then read them for yourself…they are very good! But you do as you think is best. My class is a bunch of intellectuals, they love to be challenged with complex thought…but some classes are not and that's ok too. Everyone is different.
To have a little fun, we watched STAR WARS, Episode IV, A New Hope. This was our illustration because it had some interesting similarities with the Armor of God.
Well good luck to ya with your class.
God Bless
holysoldier5000