What's your secret? ;)
I get better at writing by reading people who write in a way that I admire, and that inspires me. It may take some time to notice, but eventually, you will start picking up pieces of what they do and how they do it, and you will be able to apply what you absorb from their writing, the tricks, devices, etc.. in a way that is true to your own unique voice!
I think there's also something to be said for not being afraid of trying out words out of the context you're most accustomed to seeing them. Don't be afraid to use a word that might seem odd at first next to another word, don't be afraid to use a word that might feel unconventional in a slightly off kilter sort of way... because it might just work.
I think this kind of creativity takes courage, but it's really critical to discovering your own style, and also, it's important to practice this to "get to know" words better, what they like and where they like to me, and where they might fit, however unexpectedly.