I have found that I wake much more effectively when the alarm is very quiet; rather than waking suddenly and having my brain rebel, I wake over the course of 30 second to 2 minutes. This works much better than it has any reason to.
The downside is that a very quiet alarm is easy to miss, and if there is environmental noise at the same time as the alarm goes off (from the air coming on to trash pickup), it's much too easy to sleep through. The solution that worked best for me was to run a white noise generator (actually an air filter) all night; this raised the noise threshold so that a louder alarm was needed to still be a quiet-but-audible alarm; the louder alarm is loud enough to be heard over the white noise, and thus loud enough to be heard over any environmental noise that is not also loud enough to wake me.
Another useful trick, albeit slightly more painful, is to get up at the same time every morning. This means also on weekends. It really does help, but requires that you are willing to actually wake up enough to get out of bed. Once you are 'up', you may decide to just read Facebook for 5 minutes before going back to bed (I usually just went to the bathroom and then read in bed for 15 minutes before falling back to sleep). I only use this when I have a significant change in schedule, and only for a couple of weeks.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.