Intention and habit. If you strengthen the intention of waking up before going to sleep, you can wake up and get up better. If it's a dreadful morning you'd rather sleep through or nothing you want to get up for it'll be a hindrance.

If you have a habit of dismissing the alarm and sleeping again, I'd definitely put it not right next to me but a bit away, where I would at least have to stretch or move out of bed. Make it harder to immediately fall back to sleep.

If you slept two more hours, maybe you needed the sleep though? :)