What type of writing do you best like to do? Do you prefer books, poetry or magazine articles?
Each has distinct mojo -- pitfalls and rewards. I say, work at all three to develop writing muscle. Books allow for sustained expression on a theme, symphonic development, thrilling discovery along the way. Poetry offers the hard-won joy of distillation. Articles, with their demand for relevance, immediacy, and appeal, keep the writer's feet on the ground. Ease of publication can affect our writing preferences, but fiction -- hardest in that respect -- stirs my soul in those old irresistible ways. 

A Few Words with Arthur Plotnik in POWER WRITING by Daphne Gray-Grant