I have a question.

I'm working on the technique, "Hypnagogic Imagery" and when ever I close my eyes, they'll keep twitching. Also I had stared at the images for 15 minutes, with no result, the images were still flashing lines, dots, or odd shaped things. I tried it again and I fell asleep to a non-lucid dream, can any one just give some advice and tell me what I'm doing wrong?

Thanks.