In the past, I would add more color to a photograph by using the Saturation Tool.
Here is an old photo of my brother, dad, grandfather and great grandfather taken around 50 years ago.
The photo is a little faded and has dulled over the years.
Vibrance is a newer feature in Photoshop since CS4 that I've fallen in love with so that now, I hardly ever use the Saturation tool. Virbrance is a huge improvement over Saturation!
Take a look at my experiment below.
To get to the Vibrance tool go to Image > Adjustments > Vibrance.
Here you will see a slider by to adjust both the Vibrance and the Saturation. (note: Saturation adjustments can also be found under Image > Adjustments > Hue/Saturation.)
Saturation used to be a helpful tool but it has one major flaw. It destroys skin tone!
Vibrance is a great tool especially if people are in the photo.
Notice that in the photo on the right, the sky, blue overalls, and the yellow flowers on the ground pop with color and the skins tones are still good.
And of course, using an adjustment layer to make these changes is always the best solution keeping the original photo untouched.
The next time you want to add more color, try using Vibrance.