Theres one reason I find WILDs difficult and its becuase I twitch quite often. The first time I ever entered sleep paralisys consiously was when I listened to a self hypnosis audio file and it told me to concentrate on flying in an island and then seeing a beautiful women. So I can start SP quite fast but once I feel it starting and I focus on my body while trying to keep my mind working I start twitching. I think what I often read is not to get carried away by Hi or day dreams but for me this is only way I can fully get into SP. Not sure if this is what your meant to do but I cant SP fully when I start to think about it?