to keep the sun off my head, I usually wear an Outback style hat. If it gets hot, I dip a bandana in the water and wrap my head before putting the hat on. Sun stays off my face, head stays cool.
Another useful item is the Buff (from buffwear.com). wrap your neck, head or face. use it as a bandana, beanie, balaclava, scarf, headband. They’re incredibly useful.