I agree with the top five things mentioned in this blog for summer running.
3. Sun Block
4. Skin Lubricant
Hydration is essential. I use a nathan running Belt like the one pictured for most runs. If it is a longer run I use a 100 oz. Camelbak.
Hats are essential for me. I sweat a lot and Headsweats Hats seem to do the best job of keeping the sweat out of my eyes.
Sun Block is where I struggle. I typically don't wear it unless I know I am going to be out running for at least an hour and a half. Most of my routes are pretty shaded by design and I have never gotten burnt while running.
Skin Lube is a must for longer runs. Chafing is Bad News. Prevent it by using Body Glide. Just don't mistake it for deodorant like so many people do, myself included.
Sunglasses are very important and will keep you from squinting which actually slows you down and tires you out quicker. I use the New Balance pair below. I reccommend a pair that is Polarized. Spend the extra money, they are better on your eyes and much clearer to look through. And maybe it is just this pair but I feel like they don't fog up as much as compared to my older New Balance pair that is not polarized.