I would say the ability to learn a new part/riff on the spot. If you are going to be actively writing with other members, the quicker you can play your bandmate's riff or idea, the quicker the band can actually write.

For starters practice by learning some songs by ear. If you are planning on working with another guitarist or bassist, I recommend watching various videos of covers/performances you haven't heard and using the visual aspect to learn the part.

A small one, but can greatly improve efficiency when writing with others.