Here's a great guide from Michael Gorman that goes through ten steps to transforming past lessons for 21st century learners. There are some great ideas there, including:
"3. Incorporate at least two 21st century skills – You may wonder why I state two. First, I don’t think it will be difficult… and 21st century skills are so important to our student’s futures. You may actually find your project will incorporate a large number of these important skills. Second, in using two 21st century skills, you will be sure that one is measurable on a rubric. Research indicates that the three easiest 21st century skills to measure include critical thinking/problem solving, communication, and collaboration"
Ten Steps to Transforming Past Lessons for 21st Century Learners | 21 st Century Educational Technology and Learning