There is no scientific consensus on exactly how to initiate or prompt lucid dreaming, or if it even is a real phenomenon. Lucid dreaming advocates suggest a series of techniques to help the brain gradually learn to lucid dream, however. These include dream training, mnemonic techniques, and electronic devices.
The Lucidity Institute recommends a series of steps to train the brain to lucid dream. They suggest that improving dream recall is the first step, as the ability to recognize features of a dream may help prompt a conscious realization of being in a dream. The core exercise is writing down as much of the dreams as can be remembered immediately after waking up.
Mnemonic techniques may also induce lucid dreams. This involves attempting to recall dreams as completely as possible after awakening, then repeating a phrase or mantra when returning to sleep. Morning and afternoon naps may also be more conducive to lucid dreaming.
Some electronic devices are sold that purport to induce lucid dreaming, but they are generally not regulated and have not been subject to scientific testing. These products generally consist of a pair of goggles that block outside light and flash their own internal lights. Some also use sound.