Carry the right fluids, skin and eye products, and know how to react to an emergency. Put together a checklist and go over it before each trip. Replace fluids constantly. As long as your body has enough fluids, it can usually keep pace with the heat. Bring plenty of water and drink it.
Sports drinks are good to carry for emergencies.
Avoid alcoholic drinks, including beer, because alcohol actually dehydrates the body. It would be better to simply pour the beer over your skin to cool yourself down than drink it. Most authorities recommend a sunscreen with an SPF factor of 15 or above. Check the lip balm to make sure it has an SPF factor to block ultraviolet radiation. Choose clothes carefully.