Let's get this straight, post processing is NOT about saving a bad shot. The job of a photographer is to capture a good viable image in the camera. But, without post processing, the image is not done. "Right out of the camera" is not a bragging right or some sort of heroic shot. It's an incomplete product. Post processing involves steps that prepare the image for final "high quality" output and it is necessary.
Personally, I use Aperture exclusively. I will only use Photoshop if I need pixel manipulation. Typically, that means brushing or cloning something out from a delicate area. Aperture has a spot and repair tool... but it's still not quite "there" if I have extensive cloning or severe dust removal (especially with a pan shot).
So... that aside, here's the basics on my post processing routine. Obviously, I won't go through this on the final sort from an event. But any picture being posted or distributed will be post processed.
What we want to do is tighten up the image. All DSLRs run a low pass filter. Its job is to remove the "jaggies" in digital images. If you can picture blowing up the letter "W" font to 1000% enlargement, you'll see the staircase that pixels create... those are "jaggies." The problem with the low pass filter is it robs us of detail. Hence, the reason for unsharpen mask or what we call sharpening. You'll always want to apply your sharpening LAST.
Second I bumped up the levels. In Aperture we have a tool called "Exposure." I find that by adjusting the Exposure, Brightness and Contrast, I get a lot more "pop" out of the image.
Next I will adjust the saturation. You can do this two ways... "Globally" to all colors, or by individual color. You can get away with a "touch" globally... but you'll want to be very careful you don't blow a particular color out and start losing shadow and detail. Reds can be notorious. I'll use individual colors to control what I want... often I want to push up the sky a bit. There are two elements to saturation. One is Saturation.. the other is Luminance. You need to coax them both along a little bit at a time.
I "might" use a "touch" of noise reduction before applying my unsharpen mask or sharpening. (same thing) Again... always watch for loss of detail.
Finally, sharpening. This has to be done delicately. I won't attempt to give you specifics since I don't use Photoshop anymore. But do some research and you will see "starting" points for the settings to try. In essence, unsharpening mask in Photoshop is throwing a slight bit of contrast under the edges... this gives the appearance of sharper edges. But your dealing with individual pixels... so if you go to far, you'll end up with a crunchy kind of look an edge of things. If you get it right, you'll know. It's the same visual sensation as when a lens snaps into focus. Start of conservative.
Play with your adjustment tools. Take them from one extreme to the other and watch what they do. One of the things I noticed going from Photoshop to Aperture was the difference in the output relative to each adjustment tools slider. It's what I call "friction." Once I got the feel for Aperture's sliders (which seem to be much more forgiving than Photoshops) I never looked back.
Most importantly, learn to be delicate in your post processing... don't over do things. You're not playing a bass drum... it's a violin... subtle.. delicate.. precise. After awhile, you'll get comfortable. You'll know what images to push the limits with and you'll know where to hold back a bit. You don't treat portraits the same as landscapes and so on. Ultimately, it becomes part of your style.
No one said it would be easy... but if you can get a handle on your post processing, it will take your pictures to a new level.
And seriously, forget saving BAD images. It's not going to happen. Sure, there's a time or two when there's the image you have to have... so you do what you have to do. But there are no silk purses being made from sow's ears here.
Get it right though, and you can end up with images and colors like this: