You have to "know your audience." This means you need to know your employees, bosses, or colleagues as people and work to understand what motivates them. This is challenging, risky, and requires an opening of the mind to not just understand different psychologies but to accept them as viable alternatives to your own.
NVC communication will be very effective for some and thoroughly ineffective for others, and if you know your audience you'll know which is which.
I'm an example of the latter: I absolutely despise the NVC communication pattern because very few people actually speak like this and when they do so it's an obvious deviation from their status quo. It feels fake because it is, and it feels fake because I know the pattern. It's like when I get "feel/felt/found"[1] from a salesperson...I know what they're doing and it's not going to work.
[1] http://www.tomhopkins.com/blog/presentation/the-feel-felt-fo...