1. Lots and lots of conversations and meetings. Either at work or at social events (Meetup.com?)
2. Very careful and mindful listening and observing. What do I mean? A large part of communication is non-verbal, and these are cultural and signal things that vocabulary doesn't. Also, tone. The rising and lowering of tone in a sentence changes quite a bit between languages, and is never properly taught IMO and unless you actively try to pay attention, almost no one realizes.
2. Very careful and mindful listening and observing. What do I mean? A large part of communication is non-verbal, and these are cultural and signal things that vocabulary doesn't. Also, tone. The rising and lowering of tone in a sentence changes quite a bit between languages, and is never properly taught IMO and unless you actively try to pay attention, almost no one realizes.