Changing Scenery Completely

Last night I had a lucid dream. In the dream I wanted to go to a world in which I had created in real life, so I did this by running through a doorway. As I was running through, I pictured the world in my mind, and I was soon in a dark expanse. I tried frantically to create the world, picturing it in my mind very clearly, and eventually I started to get a feel of the world and started to smell some of where I wanted to be. The dream then faded.

What I am asking is, why did I fail? Was I using a wrong technique? Was I trying too hard?

Thank you in advance for any answers that you might give.

I forgot to say this, but as the dream was fading I tried using techniques such as shouting "CLARITY" and spinning, but they weren't working at the time for some reason. I got a bit of vividness out of CLARITY but it soon wore off.

Maybe you were at the end of your REM period. That can't be helped. As you continue, you will become lucid earlier in the dream.

Maybe you were trying too hard, in which case you awakened prematurely. Practice will heal that.

In both cases, practice is the remedy.

I've noticed that whenever I go through an abrupt complete scene change (as opposed to a gradual change, such as flying somewhere), a similar black out happens. It's a clash between the where that we originally wanted (where we start our dream), and the where we want to be. The black out perhaps occurs when the brain tries to decide which where to generate.