By taking the extra measures to physically move to another room to attempt AP, I think is causing you to prep your body and mind for it. But there are things you can do to mentally prep, one is to induce lucid dreams. You can do this by creating a reality check, it can be anything like checking your fingernails every couple hours but it has to be something you wouldn't normally do unless you were doing a reality check. And make sure its the same reality check every time you do it, once you get in the habit of this new routine your sub conscience will want to do it while you are asleep, and trust me. When you do your reality check in a dream, you become very aware that you are dreaming, and everything comes together. You can then directly transfer(with some practice) from your lucid dream to a projection. When I'm lucid its for a very short amount of time, I use that to project because for me its easier to project from lucidity than full consciousnesses because you are already half way there. When my lucid body starts floating up, is when I feel myself leaving my physical body.

edit: I can definitively tell the difference between a lucid dream and a projection. In a lucid dream, I become conscience and aware in my dream, but I'm not exactly in control of anything. I can move my body certain ways just like in the real world, but the dream still has a course of it's own that I have to follow, I can't change events. If I'm on a bike in a lucid dream, I'm on a bike and there's no changing that. But if I stand there and make a conscience effort to project, then I start leaving the lucid dream and enter a much more free realm.