Elements of Fiction: Mood

Mood creates a tone for a particular scene. Mood is usually created to foreshadow events that will soon occur. Without mood, the story fails to excite emotion. There's a couple ways to create mood.

Actions and Thoughts
No matter how dark the alley, if your character is whistling cheerfully, completely unnerved, the scene will end up far from sinister. To create mood, use a character's actions and thoughts to reflect future events. Example;

Jack glanced up furtively, drawing his coat closer. Why did I come? He asked himself silently. He stamped his feet against the cold and peered down the darkening street. Jack fingered his knife's bone handle. If Michael doesn't arrive soon...
The sound of voices made him start. Jack pressed himself against the worn wall, gripping his blade tighter. Kill first, ask questions later.

We can tell that the character is wary, even desperate. This sets the stage for suspense.


Details
The setting itself can add to a scene's atmosphere. By highlighting aspects of a character's surroundings, you can manipulate the mood.
"A cold wind nipped at his coat like a stray dog" conveys a different emotion than "A cool breeze playfully tugged at  his coat."
Let's try the same paragraph, but focus on the character's surroundings.

A cold wind blew back his coat, revealing the knife tucked in his belt. His footsteps echoed down the darkening street. The noise startled two ravens, which leapt to the skies, cawing. A tattered flag writhed atop a roof, declaring the building below to be the inn he was searching for.

The way you describe a setting greatly influences the mood.


Now let's try combining the two methods and see the effect.

Jack glanced up furtively. A cold wind blew back his coat, revealing the knife tucked in his belt.He quickly drew his coat closer, fingering the knife's bone handle.
His footsteps echoed down the darkening street. The noise startled two ravens, which leapt to the skies, cawing. He glanced up, pausing. A tattered flag writhed atop a roof, declaring the building below to be the inn he was searching for. Jack ducked onto the doorstep.
Why did I come? He asked himself silently. He stamped his feet against the cold. If Michael doesn't arrive soon...
The sound of voices made him start. Jack pressed himself against the worn wall, gripping his blade tighter. Kill first, ask questions later.