Unfortunately there's no secret to staying young & beautiful. However, there are definitely steps that you can take to prevent premature aging. Taking care of your skin by using SPF when you're in the sun and moisturizing everyday are definitely helpful measures. Also being mindful of your diet, exercising, and drinking lots of water like you mentioned will also promote healthy and natural aging.

WebMd has a great article that would be helpful for you to read, it's about eating for longevity.