You should also know that shooting RAW will typically allow a bit more exposure latitude as straight-from-camera results generally do not fully utilize the entire exposure capability of the camera.
Here's a link for postprocessing work in Photoshop w/ various uses of histogram in post work:
Look through the pages to see how histogram can be used during postprocessing -- and also more details on what's really going on underneath. Unfortunately, there's no way to provide usable direct links to specific pages, so you'll have to browse on your own. The site is fairly concise and easy to follow, if you have Photoshop.