What, if anything, works best for you to hear, see, or feel inside a dream? Such as an alarm that lasts a few seconds - just a ringing sound, or music, and for how long? Or does flashing lights or something like a vibrating cell phone work well?

So far I've tried a few combos of buzzing and slow bell sounds that last 2-10 seconds, every 20-30 minutes, but they only seem to succeed in keeping me from getting deep sleep. I never hear them in my dreams, in fact dream vividness seems to be harmed because I don't sleep as good. Where have I gone wrong?