Regardless of what your audio track is for, there's always room for improvement in post-production. Tweaking the stereo, adjusting the EQ, or even just giving the track more of a polished feel are all very important.
Using the right tool for the job can improve product quality, but with so many tools and so many jobs, where do you even start? Knowing what changes to make, or at least some common areas that need to be adjusted, can really help you get started.
The article that follows lists several tools - not software programs, mind you - but the tools you can find both as software or hardware, though in today's home studio, we'll mostly be talking software.
All 10 of the tools mentioned (such as EQ, limiters, compressors, etc.) can be found in most audio editing programs, such as Adobe Audition or Sound Forge. Personally, I use Audition for post production work (primarily mastering). But other programs are just as good.
Take a look at this great set of post production tools and some of their suggested applications here.