There is a method of inducing lucid dreams that is getting a lot of love on Reddit at the moment. The FILD method is described in this post, but the technique can be summed up as follows:

1. Go to sleep.

2. Wake up when you're very tired, perhaps using an alarm.

3. Start tapping two fingers very gently, using a minimal amount of energy. Keep tapping and let yourself drift off to sleep.

4. Do a reality check after a few minutes.