Dickens uses many techniques, including idioms, hyperbole, and imagery.
Figurative language is used throughout A Christmas Carol by Charles Dickens. It is language not meant to be taken literally. This helps to make the book more enjoyable by creating pictures in the reader’s mind. Dickens makes use of many different types of literary devices, which are tools an author uses to add color to the work.
One such literary device is an idiom, which is a type of figurative language. It is a saying that has been used by a culture over and over again until it becomes common knowledge. Here is an example of an idiom.
He felt that he was restored to consciousness in the right nick of time, for the especial purpose of holding a conference with the second messenger despatched to him through Jacob Marley's intervention. (Ch. 3)
You are probably more familiar with the phrase “in the nick of time,” but it is the same thing. It’s an idiom that means just at the right time, or before it is too late. Scrooge means that he work up just in time to meet the ghost.
Hyperbole is a literary device where the author exaggerates, usually for humor. There is a great example of this here.
Without venturing for Scrooge quite as hardily as this, I don't mind calling on you to believe that he was ready for a good broad field of strange appearances, and that nothing between a baby and a rhinoceros would have astonished him very much. (Ch. 3)
The point is that Scrooge is so nervous, and has had so many surprises tonight, that nothing would surprise him! He knows that ghostly intervention is afoot, and he is ready for anything.
Imagery is descriptive language. Consider the use of figurative language, such as a simile and metaphor, or sensory details, which use the five senses, to create pictures in the reader’s mind. In the description of the room that the Ghost of Christmas Present "decorated," Dickens uses both.
The walls and ceiling were so hung with living green, that it looked a perfect grove; from every part of which, bright gleaming berries glistened. The crisp leaves of holly, mistletoe, and ivy reflected back the light, as if so many little mirrors had been scattered there; and such a mighty blaze went roaring up the chimney, as that dull petrification of a hearth had never known in Scrooge's time, or Marley's, or for many and many a winter season gone. (Ch. 3)
The simile in this example is “it looked a perfect grove,” meaning that the room looked like a grove of trees. Another example is that it looked “as if so many little mirrors had been scattered there” because the leaves reflected back the right. The other descriptions are decorations and food that are throughout the room, so the description of the room is very colorful and interesting.
As you continue looking, you will see other examples of literary devices that Dickens uses. These will enhance your appreciation of the book, as they are used by Dickens to create the world populate by Scrooge and the three ghosts, and all of the other characters.