This is how I use to fall into Sleep Paralysis. I figured I share this with you just in case your struggling with other methods. I guess this is my own variation on the WILD method.

I know some of the tutorials tell you to stay completely still, but this is sometimes not the case. Before I found this website I use to induce SP in a entirely different way and it still worked.
My technique requires you to have a good imagination and be able to play out story's in your mind.

When I wanted to enter SP, all I would do is lay in a comfortable position on my bed, close my eyes and play out a story in my mind. This keeps my mind awake because I am concentrating on the story and eventually my body will fall asleep.
I know it sounds silly but I would lay there and imagine myself fighting a horde of zombies or something. I would play it in my mind as if it was a movie.

After a while you would get so in depth with the story that you forget about your body. Your body just assumes your mind is asleep.
Sometimes the topic of the story would shift as your mind starts to wonder. This is normal.
I am sort of person who likes to think a lot, and before I go asleep I would always fall into to deep thought. Every time I did this I would have SP.
As long as I didn't fall asleep, this would always work. Sometimes just the anticipation of seeing the end of the story would keep me awake.

I am not saying this will work with everyone, maybe its only specific to me. But I hope it will help somebody out there.