You use the typical MILD technique but what I found out to improve the MILD technique you basically you record an audio file with your voice saying for example: "I will wake up in a dream" or "I'm dreaming" and copy-paste the audio-file to repeat itself throughout the duration of how long you want it to be said. While the audio plays what you say, repeat it in your mind also. I realized this helped me a lot with MILD because my mind can easily wonder off as I try to fall asleep.

Example of my Audio Mantra

What I added in the background of the audio I created was a couple of songs that makes my mind spark imagination which helps me into creating an environment in my head while repeating the mantra. If you consider doing the same thing, pick out a song that makes your imagination spark but also make sure that song does not have any lyrics because those lyrics can ruin your mantra and make your mind think about the lyrics. Instrumentals work the best, also I added an Isochronic tone in the background (Not too loud) that promotes your brain to get into a pleasant dreamy state. I preferably made my Audio Mantra 10 minutes long and when I'm done listening to this, I take off my headphones or turn off the audio and what happens is that my brain keeps on repeating the mantra over and over again until I just fall asleep. If you want the Isochronic tone here is the download for it: Zippyshare.com