Supporting with common skills

As one who has worked in middle schools where grade levels are teamed in core content classes, I have seen and heard the difficulty of the humanities supporting the sciences. The quintessential question in teaming is “how can math and social studies teachers collaborate?”

We should seek to collaborate on a deeper level than simply everyone teaching a unit about Galileo. A truer spirit of collaborative grade-level teams would mean “what specific learning skills are essential for success in math, and how can a social studies teacher include those same skills to enhance student learning?”
What suggestions do content teachers have where they would like skill-training support from other teachers?