What is a good way to learn how to emulate the diction of Lovecraft or Poe?

I greatly admire the tone and diction with which they write, and was wondering if there are any sort of writing exercises or somesuch that would allow me to more easily think and write in that sort of style. Obviously it requires a large vocabulary and some degree of intelligence, but is there anything besides that? Something akin to how playing scales on the piano makes you better all around?