Make characters scientists. They can talk, think, act and react scientifically. You can place them in scientific environments such as laboratories. For example, make a character a geneticist. You could include a scene where he looks through a microscope and remembers the first time he heard genes called the building blocks of life.
Write a scene that involves a time or place of scientific significance. For example, you could create a scene in Los Alamos, New Mexico, in World War II that intertwines the development of the atomic bomb there with how the lives of the scientists who developed it are changed forever.
Write a subplot that involves a scientific discovery. For instance, write about a small American town during the polio epidemic in the 1950s. You could write about Dr. Jonas Salk's efforts to develop a vaccine and how much the town unknowingly depends on him.
Research the science used in your story. Look up the terms you will use in a scientific dictionary either in print or online to ensure they are used correctly. Learn about the kind of science in your story. If you are writing about viruses, study basic biology. If your story includes space travel, learn about astronomy. If you have little knowledge of science, start with a publication aimed at beginners, such as the "Dummies" series or the "Complete Idiot's" series.
"Imagineer." Yes, it is a made-up phrase. But that is what imagineering leads to: creating something new. The light saber did not exist before "Star Wars" and warp speed became a well-known term through "Star Trek."