What methods have you tried?

I found doing multiple WBTB's (and sleeping over my boyfriend's instead of my own place), and going to bed early, managed to get me out of a dry spell. With WBTB's, you can remind yourself in the night as you wake up that you will soon be dreaming again. The memory of having fallen asleep may surface in your dream and help you realize you're dreaming. They hadn't been working for me for a while, but I think they were too routinized, and I was too afraid of losing sleep.

Maybe doing something different on the night you want to LD will help too.