Dream Journal, Imagination, and Dedication.
That's all I feel the need to attest to.
I developed my ability to lucid dream, naturally, by exploring my own mind. I would lay in the bed and run all sorts of thought experiments in my own mind. I did for hours on end, every night. I did this so much that my mental imagery, focus, control, and comfort level became so high that in my dreams I would remain aware. So, I developed DILD naturally. I noticed that if I played around with the notion of sleep, instead of closing my eyes and blanking out, that I was able to reach strange states of mind, and this FASCINATED me. This quickly lead me to WILDs. I didn't have the internet back then. I lucid dreamed for ten years before I learned that there was a word for it. I really just thought of it as "Studying my brain".

So, for me, all that I needed was imagination.
Dedication MUST be important, because without it you won't even try to lucid dream, and that rarely leads to lucid dreaming. lol
And I state Dream Journal, because for the time that I had one, my dream recall SKYROCKETED.