Here, I'll summarize.
Howetzer's trying to say that in order to become CONSCIOUS in your dream, you must first understand that a dream is fully subconscious at first. Attaining lucidity is, by definition, becoming conscious in your dream (subconscious state.) You must train the conscious mind to do things that will provoke the conscious mind in a dream. This is exactly why we practice doing reality checks, even when we're absolutely positive we're in reality. Because the mind gets into a habit of doing the reality checks, the habit becomes part of your subconscious mind, therefore enabling you to do a reality check even when your conscious mind is asleep. In other words, you have to train yourself in reality before you'll be able to do it in the dream world.

Hell, I understand it, but I still can't attain lucidity. Practice, practice, practice!