They do say it's better to set your alarm for as late as you can and then force yourself up (otherwise you restart the REM cycle [by hitting the snooze button] and you wind up more tired than if you'd just gotten up).
Go to bed earlier. Count sheep, watch TV, read a book—whatever makes you fall asleep. Then let your body wake up by itself and see how long it actually needs to sleep to function.
It could be your diet too. Depending on what I eat, that will make me sleepy and I won't be able to function for the rest of the day.
For napping (which I never do) I've been told to nap loosely hanging on to a set of car keys. When they drop and wake you up you'll have achieved the perfect mini-nap.