Regularity is a key: going to bed at the same time, waking up at the same time no matter what. But I think, also, it's not just about quantity - that's what we've been discovering. It's also about quality.
Do you tend to sleep in during the weekends? That usually signals that you're trying to sleep off a debt you've accumulated during the week.
As you try to tweak your sleep one way or the other, you might be, you might be doing great - you might do better at remembering details of an event, but you might end up being poorer at abstracting the gist or the rules associated with it.