80-90% of the visible signs of ageing come from the sun. This is why, in older people, you'll find their body generally looks younger than their face. This is because clothes protected their body from the sun, but their faces were fully exposed.

Always wear sunscreen on your hands, face and neck every time you go outside. If you're the type of HN'er that is on the computer all day and rarely goes outside, doing this on the few occasions you do will take away one of the only opportunities the sun will have to age you.