The fading in and out of lucidity is common. I think you need to stabilize more often, each time you feel like awareness is fading, or every few seconds.

I think everybody has a very strong urge to fly. I found, that if I want to remember what to do, I need to practice it during day. So in your case, I would literally stand in my room and draw portals in the air with my hand. I would say out loud "OK, I just got lucid and I'm making portals to take me to..." I would do it a few times, to get a "muscle memory", since many times in LD, you take off doing something on some urge, not really making conscious decision about it, but if you practice, you will start doing it as if on urge also, but this time it will be what you wanted to do.

Unless, of course, your awareness will be 100%, then you can DECIDE, what to do. Hope this helps. Happy dreams