I set my alarm for a few minutes before I have to get up, and when I really REALLY have to be up and out by a certain time, I set one a minute after, one two minutes after, and one 3 minutes after, just so I don't oversleep
When I was a kid my Mom started waking me up a half an hour early and I hated it! She would come in and say "It's time to start waking up" which was really annoying. I was a very heavy sleeper, but I finally was able to convince her to let me just use an alarm when I actually had to get up, and if I didn't react, she could come in and yell at me. I was notorious for turning off my alarm and not remembering I had did it, so I put my alarm across the room so I had to get out of bed to turn it off, which solved that problem and worked very nicely.