I agree with style-queen, keep out of the sun and keep hydrated, beyond that I think it's down to good genes. I have always thought that the bog-standard olay fluid is one of the best moisturisers around.
Any anti-ageing stuff only has a temporary effect, something like lines caused by sun damage is far deeper down than any cream can go, so prevention is better than cure. Having said that, I am a big fan of protect and perfect because it does make my skin look and feel loads better blemish wise, so I feel a lot younger.