I believe you can learn to write by imitating models of writing. The first thing that good writers usually have in common is having read a lot (quantitatively), but also with a sense of discrimination, thinking about what makes writing effective along various dimensions (clarity, elegance, good organization, etc...)
Realistic models are those in the same language and genre in which you are working. I can learn about writing from reading Proust, but I am not writing in French. They should be relatively modern, from the early 20th-century on, say. Your prose is not going to sound like an essay by Ralph Waldo Emerson or like a sermon by John Donne. You also want a style that is not too oratorical, but that is not dead on the page either.
They should be models that solve the particular problems that you face. How to talk eloquently while analyzing poetry, without getting bogged down in literary criticism-ese. How to summarize the secondary literature without doing a "data dump." How to place voices in dialogue with one another without confusion.
A realistic model should give you hope. The academic writer whose work you are emulating is not a great genius of prose style, but someone who has self-consciously worked to achieve a level of elegance and clarity that is well within your reach too. Chances are the writer you are emulating learned from other models.