One of the quickest and simplest ways is to use Photoshop’s Levels through an adjustment layer, allowing you to leave the original image intact. To accomplish this, click the half-black and half-white circle icon in your layer panel (shown on the right here). Then, in the pop-up menu, select “Levels…”. This will pop up an editor which will look something like the shot below.
This window displays the distribution of information from dark to light across the image. Using the sliders across the bottom it’s possible to adjust the dark point, mid point, and white point through the sliders.
So, to improve the contrast and stop the image feeling a little flat, we’ll move the dark slider across (telling Photoshop to consider that the new position is the dark point—making lighter areas appear darker). We’ll also slide the mid-tone slider across to the right to make the whole image appear darker, and move the left slider in slightly to lighten the top-end. The new positions look as in the image to the right.
They’re relatively small changes, but they make quite a large improvement as you’ll see from the adjusted image to the left. Now, although this image looks far more vibrant, and less flat, it also looks markedly red. So, time to adjust things a little more to remove that redness so it looks a little more natural.
To do that, click that black/white semicircle thing again, but this time we'll insert a "Color Balance" adjustment layer in. Once that pops up, we just move the top slider a little to the left until the image looks a little better. We just want to tone the over-bright redness a little.
This leaves us with a final image as follows:
And for comparison to the original:
As you can see, the image is bright and vibrant, the blues, reds, greens and blacks are solid, and it looks much more lively. Overall, much more pleasing. The Levels adjuster is one of the quickest ways I’ve found to help a photo jump out at you, although there are more advanced ways to adjust more precisely—using the Curves adjuster for instance, maybe I’ll try and find an example to show that in the future. My next job is to remove some of the dust and other bits ‘n pieces in the mesh that distract the eye in the background.
Incidentally, I picked up this (and my other retouching ‘skillz’) through Katrin Eismann’s excellent book “Photoshop Retouching & Restoration”. It has some great walkthroughs, including some amazing work with restoring old destroyed photos. I’d thoroughly, thoroughly recommend it to anyone looking to improve their photos with Photoshop!