Alarm clocks
Admittedly we get roped into using these sometimes, but avoid at all costs. The way you wake up really affects your day, your outlook, your happiness. The way to get off an alarm clock is to first use one to wake consistently at the same time, 7 days a week. (Even on weekends.) When/if you establish a consistent waking hour, you’ll find that you wake up naturally without an alarm. The downside, of course, is that it becomes much harder to sleep in. If you do create a mental alarm clock, though, you'll find that the urge to sleep in lessens. You're happier because you've become master over your own time. 

Setting your mental alarm clock
Scientists have been unable to definitevely prove that the mental alarm clock exists. That said, a lot of people swear by it. To get going, simply determine what time you want to wake up, look at the current time and calculate the number of hours that you will sleep.  Next, tell yourself over and over that "I will get up at X:XX time or I will wake up in X hours."  You'll be amazed at how effective this technique is at waking you up at the time you desire.