More vibrant colour

I read in a book, saying that, shooting a potrait, its good to set EV value a bit higher, so that the Model look fairer, and to make the colour brighter, EV value must be adjust to slightly negative. I've take a try on it.

The one at left hand side is the one i set the EV value at 0. and the one at right, i've set it to -0.75. Its quite obvious that the left side photo's colour a bit faded, where as the right side one look better, and greener.

The one at left side is at EV value 0, and the right side EV value -1. Also seem quite obvious that the right side one has a more vibrant colour, and more details can be seen, especially at the cloud side. Whereby the left side, colour is a bit faded. But some of my friend commented that the right side photo is a bit too dark, and suggested I pull up the EV value to -0.5 intead of -1.

Well, I shall explore more on this, and share.