The Quick fix feature of Photoshop Elements is a easy way to improve the look of your images. All of these features will change the way your image looks in terms of color, contrast, shapness, brightness, etc. Multiple adjustments can be made simultaneously before you images is actually processed...this makes the process of adjusting quicker and easier; hense the name.
The Smart fix is a control which will adjust many different aspects of your image at the same time (automatically), but at the same time, this feature does not give you as much control over the result.
This area allows you to change the contrast of your image. The simplest approach is to try the auto levels button, however you can have more control over the contrast of your image if you use the shadows/midtone/hightlights sliders. This gives you the ability to adjust the contrast of your image by independently affecting the dark areas, light areas and the middle tones in the image.
An essential fact about digital imaging is that adjustment you make to your image is done by manipulating the hue,saturation/brightness of each pixel. In this area, you can adjust the saturation, hue and other aspects of your entire image. Hue is just another synonym for color. Saturation is the purity of the colors in the image (try it and find out). Temperature will make your image more or less blue/red, while tint will make your image more or less green/pink. More on temperature and tints later.
Adjusting the sharpness of your image is not a substitute for properly focusing the image when you shoot it. In fact, the sharpening filter simply creates the illusion that your image is sharper. the most important thing to remember here, is not to sharpen too much.