Talks at ThrillerFest, which I attended two weeks ago, covered a lot of ground. One of the most interesting was a panel titled “How Do You Thicken the Plot: Subplots and How to Make Them Shine.”

Of course, a strong plot is critical to a good thriller. But a single plot line can get pretty old, pretty fast. Enter the subplot.

Subplots, the panel explained, add texture to the story. They provide an opportunity for the writer to create emotional friction between characters. Also, subplots can allow writers to diffuse the darkness and violence that are so important to thrillers, saving the story from becoming too depressing. Humor can work wonders here.

The panelists provided some tips in creating subplots:

• Subplots must add tension to the story, or else they don’t belong in a thriller.
• They must feel immediate, with action. They should not be exposition.
• Put them in when action in the main story gets to be too much.
• Chart your main plot and subplots, and make sure not too much time goes by before a subplot reappears.
• Romance is a great feature in subplots, giving characters the opportunity for some happiness.

This panel featured: Wendy Corsi Staub (moderator), Daniel Friedman, Mark Greaney, J.L. Hughes, Chris Knopf, Jeremy Robinson and Emily Winslow.