How do I take proper care of my skin?

Sunscreen. Most important is to protect from the sun by using a sunscreen with spf 30 or higher and reapplying every 2 hours if you're exposed to the sun. If you're outdoors also wear a hat and sunglasses. Remember that you get sun exposure even thru the car windows and office/home windows and just walking to and from your car. Wash and moisturize.
Sun Protection. One of the most important steps you can do to preserve your skin is sun protection. That includes a good facial moisturizer with broad-spectrum sunscreen that filters out both uva and uvb rays. Over time, these rays can cause wrinkles, brown spots, and even skin cancer. Better yet, if you are planning on a spending a day outdoors, wear a wide-brimmed hat and and sun protective clothing.
Simple measures. These common sense measures are the mainstay of good, healthy skin: moisturization, photoprotection (ie photoprotective clothing and sunscreens), and... Healthy eating, sleeping and exercise habits!