Varying your sentences is one way to

define key ideas

liven your writing

aid in characterization

avoid grammatical errors

liven your writing

Adding variety to your sentences is a simple way to liven up your writing. Repetitiveness can get tiring for the reader, while a variety of words and sentence structure ensures that the reader's attention is mantained throughout the text. Other ways in which you can hold the reader's attention are a fast pace, vivid descriptions and rich imagery.

The use of third-person limited point of view allows the reader to better understand the main character.