I am a natural lucid dreamer, so I have tried only one method other than it just occuring while I sleep. Dreams are often a reflection of what happened that day. The more exciting or new the experience is, the better the dream will be. The better the dream, the more likely it is you can spot a dream sign. The only way I have tried other than that is my alarm clock. I set it to the absolute lowest setting and set it to 4:30 AM. I am such a light sleeper, even the lowest setting wakes me up though