This post was addressed directly to my girlfriend. It shows examples of some basic photo improvement techniques. These are all photos she took, and I spent a few minutes with each one in The Gimp. Photoshop can do it, too (obviously).
I post-processed the photos you sent me to give you some examples of common manipulations in Photoshop.
Color casts – when the entire color palette is shifted towards one color. Notice how your original copy is very red: the white sheets looks orange, and skin looks reddish pink. By adjusting the curve of just the red color channel, I made the colors more natural:
This photo is impressive because the bee sticks out against the background, but the background still has some interesting texture to add. Since the subject is supposed to pop out, cranking up the contrast emphasizes it even more:
The faces of the men are a critical part of the picture, but the autofocus didn’t target on them so they are a little soft. It’s hard to notice in digital copies, but using the filter called “unsharp mask” makes subtle focus improvements. It can make a big difference when printing a photo. Be careful with it, though, as over-sharpened pictures look bad. Some pictures, like the bee one above, are already sharp and running the mask makes them look unnatural.
This one exhibits atmospheric haze. Smog in the air reflects blue light stronger than other colors, and makes the background look hazy. Outdoor photos always look their best immediately after it rains because there’s no haze in the air. Haze shows mostly in the blue spectrum, so for this one I selected the top half and reduced the blue curve to drop the haze. Then I bumped the contrast a bit to help the kids jump off the background, and finally sharpened it mildly.
Here’s another one that is meant to jump out at you, but it’s so desaturated and lacking in contrast that it doesn’t have much oomph. I cranked the contrast way up, which gave the pavement a really cool texture. The leaf was still nasty and bland, so I outlined just the leaf and saturated the colors heavily.
This one is excellent framing, but the colors are muddy and too similar in intensity, and the bird is a little out-of-focus. It needed something to make it exciting, and I couldn’t get the colors to jump out enough, so instead I desaturated it (turned it black-and-white) and railed the contrast so the background turned solid white and the bird’s wings turned solid black. There are some artifacts in the leaves now, but the overall image pops more.