There's a difference between principles and tactics.
Principles are higher level concepts that are critical to success.
Tactics are specific actions and tools to achieve a specific aim.
Tactics change and adapt, but principles never change.
When it comes to mastering lucid dreaming you will encounter many different techniques and strategies along the way. However at the end of the day you should focus more on understanding the principles behind lucid dreaming.
With that said, here are the 4 Underlying Principles For Lucid Dreaming (Dream Hacking):
1 - Self-Awareness
Self-awareness is your ability to be in tune with your thoughts, feelings, and environment.
If you are lost in your thoughts, anxieties, and constantly live in reaction to the world around you, you will have a much harder time becoming lucid in your dreams.
Lucid dreaming requires you to be aware of the world around you and think critically.
If you lack self awareness in your waking world you will also lack it in the dream world.
2 - Beliefs and Expectations
Our beliefs and expectation already play a large role in how we perceive our waking world, but they play an even bigger role in our dreams. For example, the rules of gravity, and societal rules no longer apply in the dream world.
If you want to learn how to fly, teleport, explore your creativity, and meet certain dream characters in your dreams, you need to change your expectations about what is and isn't possible.
Therefore, you must learn to cultivate a flexible mind and be willing to question your beliefs about the nature of reality. You must also learn to keep in mind that your intentions play a large role in your ability to have lucid dreams.
Every night before going to bed you need to make a firm intention to lucid dream. You can't just leave it up to chance if you want to have lucid dreams on a regular basis.
3 - Motivation
You will not master lucid dreaming overnight.
You need to develop the motivation to preserver when times get tough.
If you lack this motivation you will have a difficult time mastering lucid dreaming.
4 - Memory
You need to cultivate your memory in order to consistently have lucid dreams. You need to be able to recall your dreams, remember to perform reality checks, and remember dream signs.
Even if you think you have a bad memory, that's fine. Memory is skill that anyone can improve through consistent hard work. I would know - before I began training for the 2014 Canadian Memory Championships, my memory was considerably "below average". However with some effort and through consistent training (usually in my lucid dreams!), I won the championship.
If I can improve my memory, so can you!
Now that you have an understanding of the 4 underlying principles, your first step to learning how to lucid dream is to keep a dream journal.