Whenever I have shared this technique with anyone they have been amazed at how it works. I have always awoken naturally without an alarm clock and visualise the time in my mind before going to bed.
Imagine a clock – the old fashioned ones with two hands. Visualise the time that you are going to bed. See the hands turning. As they turn, imagine you are going deeper into sleep. As the hands turn and get to an hour before you wake up, feel how your body is becoming more alert and awake. At wake-up time, physically open your eyes and feel joy at waking up. Then repeat the visualisation again.
Repeat this visualisation several times as you are falling asleep.
Seriously, your mind and body are amazing!
Let me know how this worked for you.
If you are doing this for the first time or you have to be up for something important, I would suggest putting an alarm on until you are totally confident with this method.