What is the first sign of dehydration

One of the first signs of dehydration is almost brown coloured urine, and extreme thirst.

Loss of elasticity in a skin fold also demonstrates elasticity. Pinch a fold of skin and watch it quickly drop back into place. Then do the same in a dehydrated person. The skin fold will very slowly resume its place.

People's profiles are important because they show you who they are unless they're fake.