Straighten Out Buildings
If you work on the exposure and colors, you'll have dramatically better photos. But then you might start to notice smaller problems--like crooked buildings, for instance.
Take a photo of a tall building, and you might notice that it looks a bit like it's leaning, or even warped. You can thank a phenomenon called perspective distortion.
If you have Photoshop Elements, you can reduce the intensity of this distortion by choosing Filter, Correct Camera Distortion, and then adjusting the Vertical Perspective. This reduces the apparent perspective distortion, though you'll need to crop the photo to eliminate the tapered bottom.
A better solution is to try a plug-in designed especially for perspective correction, like Andromeda Software's LensDoc 3.0 ($119), which works in any program that supports Photoshop-style plug-ins, like Photoshop Elements and Corel Paint Shop Pro.
If you have Paint Shop Pro, use the built-in perspective correction tool, which works amazingly well, and doesn't cost anything extra. See "Fix Perspective in Architectural Photos" for a tutorial on using that tool.
Related knowledge of photo editing software: