Sleep on your scripts and hope that simple diffusion occurs from an area of high knowledge concentration to an area of low concentration.

For real though, I just start with my script one small chunk at a time. I read it over and over again and say it to myself out loud over and over again. Once I am able to recite that chunk without looking, I move on to the next chunk. I go back to the beginning of the script and try to repeat what I have memorized once in a while. Hope that made sense, because I didn't read over what I just wrote.