I envy Bill Watterson for the mood he sets in his Calvin-waiting-for-the-bus-to-come scenes, especially his rainy ones. When you look at this image, you probably have the same reaction that I did: wet, cold, and miserable (the kind of miserable that you get when you’re doing something you love and then are interrupted to do something you hate).
However, such is the mood of this strip. The crazy thing is that the actual art serves a more minimal purpose here: the misery that Calvin exudes comes mainly from the tale he’s telling to Hobbes and its juxtaposition with what’s about to happen, and neither is illustrated. The illustration mainly goes to show you that it’s raining.
It’s not so hard to create a mood. You just have to get the reader to partially picture a feeling. Nuts as this may seem, the mood is dictated by what the characters are feeling, or on the feeling you want to give your readers if there are no main characters around. It’s all about what the reader feels upon walking into that shady alley, the smoky bar, or the cozy and simple abode.
However, the things in the setting dictate the mood. Here’s how it works: the first impressions, words and descriptions will give the reader a sense of mood. They will begin to develop this mood and see things in light of it. This enforces the mood in the scene, which in turn enforces the mood in the reader’s mind.
Writing is 90% mental and reading is 100% so. To give your reader a first impression of the mood, utilize the physical light of the scene. You heard me: tell the reader what kind of lighting there is. You’d be surprised how much work a little word like “dark”, “light”, “dank”, “gloomy”, “dusky”, “tenebrous”, “lucent”, “glistening”, or “lustrous” can do.
Tell the reader what the light spectrum is like, and then tell its effect on the objects in the vicinity. So if there’s a bunch of hoboes crouched in a corner just beyond the light of the scant light the streetlamp affords, how do they look? Do they look…sad? Peevish? Afraid? Hostile? All excellent words you could use to describe things just based on the lighting.
Next, what do the main characters think or feel? Remember: it’s about what the reader feels, not necessarily how the characters do. However, if your readers have empathy for the characters, then odds are your readers will feel the same way your characters do. This still doesn’t prohibit you from telling readers what the characters think as well, though.
Picture yourself as the character in the setting as part of the mood. What are they thinking? What are they feeling? If this person hangs around these places often, it probably feels like home to them. If someone doesn’t, they probably feel miserable and alien. Delve into the minds of your characters to find out what they think and feel to set the mood.
But that’s pretty much it. As a rule of thumb, try to put in as many things that stimulate vivid mental images as possible when setting the mood. Images evoke feelings, and the more intense the image, the more intense the feeling. Use as much mental imagery as possible when creating a mood.
Good luck, and happy writing!