Style is something that is developed over time. As writers, we all have our own styles and ways we like to write and express our creativity. There are many elements of writing that contribute a writers style, but of the most important are word choice, sentence fluency, and voice.
Word Choice is incredibly important when developing clarity and detail in any type of writing. A good writer will choose words that contribute to the flow of the work. The use of sentence fluency is important because it helps the writer develop sentences that vary in length and rhythm. Voice lets the writer put their own spin or personality into the work.
Style is in every piece of writing we read. The elements that go into it are important because they make the work unique.
Cite: http://www.learnnc.org/lp/editions/few/684