There are endless amounts of methods and techniques used to induce lucid dreams. While there are many pills and other one-step methods claiming to instantly admit them, it is widely believed that no technique works better than music and special frequencies to influence the brain's awareness state (brain wave patterns).
There are four known brain wave patterns:
The Beta state is when the brain is most aware. It occurs during concentration, alertness, cognition and arousal. It is the state that most humans spend the majority of their day in.
The Alpha state occurs during pre-sleep and pre-waking (the stages before and after sleep). It allows for the body to be extremely relaxed and increases production of serotonin, an extremely useful neurotransmitter that boosts your brainpower.
The Theta state is the brain's dreaming sleep, otherwise known as REM sleep. For lucid dreaming, it is the most ideal state to be in.
The Delta state is the deepest brain pattern. No dreams occurs during Delta – the body enters a trance-like state where growth hormones are released.
Sine wave generators are used to generate frequencies that essentially move the brain into remaining in one particular state, mainly Theta. They guide you into normally entering the Theta & Delta states, but before re-entering the Alpha state, they "dip" you back into Theta. While your conscious mind holds sleep, your subconscious is confused into thinking that you are awake but quickly realizes that you are still dreaming. This then Promotes lucid dreaming as your subconscious remains wake.