1)Sleep-Sleeping Beauty always had porcelain perfect skin
2)Hydration-2-3 litres a day, no less. Liquids other than water are counted. But for every cup of coffee, drink twice the amount of water. For every cup of tea, one cup of water. (I know some people insist that tea doesn't dehydrate, but it is a diuretic after all. So better be safe than sorry.)
3)Cleanliness-Need I say more? Hands off your face!
4)Diet & Nutrition-2000mg Vitamin C daily is the bare minimal. The body does not absorb all that it ingests, so you need most probably need the extra. You need it for repair of body tissues, to fight off illnesses, so by the time it comes to your skin, little is left for anti- aging and repair. Other supplements ( including but not limited to (Vitamin A & E. Ask your friendly local pharmacist for advice.)
Coming up soon: a writeup on vitamins.