Use sun cream product. You can also wear sun glasses. Drink a lots of water during a day.
Answered Mar 07, 2013
Edited Mar 07, 2013
Also, avoid staying out in flat open areas that lack shade. Heat stroke is a very dangerous thing.
Seek shade when in the sun especially when the uv index is at its highest between 10 am to 4 pm. Use a hat or an umbrella as most sunscreen creams are mildly cancer causing.