/vp/, how do I into Doubles? The 6v6 Singles metagame has gotten real stale and I'm looking for something new. Plus, GF's been pushing the primary battle mode to be doubles/triples for a while now, so I should've learned a while back anyway.

What are some key things to know when getting started and teambuilding in the Doubles metagame? What are some big differences between it and Singles?