Decide what point of view you want to use in your story. The point of view can be either in first ("I"), second ("you") or third ("he/she") person. While you can have more than one point of view in a book, usually a single scene will be written from the point of view of one character. Allow yourself to write as the character in first person freely before you start the chapter. Even if you want to write the chapter itself in third person, writing from the character's point of view in first person can help you capture his voice.
Write the chapter, keeping in mind the voice of the character that you established in Step 1. There is no right or wrong way to write in prose; it is simply a matter of finding your own style. Write long, thoughtful sentences for stream of consciousness prose, or write short, clipped sentences for choppier prose. While you should monitor yourself, do not worry too much about editing at this point. Instead, try to see the scene through from beginning to end.
Revise your chapter. Read it through once, paying close attention to your writing style. Reading aloud is extremely helpful when it comes to finding your own style. Ask yourself as you read if the words and story flow, or if the chapter falls flat. Identify your strong paragraphs and sentences and figure out what makes them strong. Edit and revise, making sure you make each word count.