Miss H
Thanks for your question.
I recommend looking at the National Standards, which are broken down by grade level and ability. By look at these, you can focus on the skills you want to assess and create rubrics.
http://www.tesol.org/s_tesol/seccss.asp?cid=113&did=1583
Remember you want to begin with the end in mind. What do you want to students to be able to demonstrate in class? I think these National Standards will give you a good starting point and framework. From there you can do further research in designing projects, effective teaching strategies, and authentic assessments.
Keep the questions coming!
Andrew Miller