I myself have not been able to complete the SP stage, but I can get to it no prob. I did try the Rapid eye movements, and I think that just makes you light headed, or a little dizzy. It definitely feels different from the onset of SP. All I can tell you is allow your self to breathe in shallow, quick breaths. Don't force it though. Your body will require less oxygen as it shuts down for the night, but breathing shallow when your body isn't ready for it will just make things harder, if not wake your up more. I just take deep breaths, think about something, and then, after a bit, I slip into my natural sleep breathing rhythm. I found that if I think about something, not to intense mind you (Like a game I've played, or a movie I've watched), but something to distract yourself, while keeping the fact that you need to remain conscious in the back of your mind, it is a bit easier to slip into SP.