They Say, I Say is filled with templates to support students as they draft arguments, and here's a google doc with templates and transitions.
Connecting to the Common Core is filled with lots of resources.
In the files below, you'll find some ideas for teaching argument. In addition, "Claims, Claims, Claims," provides ideas about teaching claims.
The Teaching Channel is filled with great ideas and teaching videos.
NSA (National Science Association) had published a document called 8 Strategies for Designing Lessons Plans to Meet the CCSS Opinion and Argument Writing Requirements
The Structured Controversy is a great way to teach students to consider counterclaims.
This Scoop It site has links to possible mentor text, cool instructional strategies, tons of possible argument topics, and loads of other ideas.
Check out Teach Argument for ideas