Here's a small list of tips & tricks in Photoshop.
- Work mostly non-destructively:
Always use adjustment layers instead of working directly on the layers themselves. This allows you to come back to a processed image and adjust a few things if you need to later on. It also often saves on file size.
- Tune exposure throughout the image:
Instead of painting with a white low-transparency brush in some kind of multiply or screen mode layer, a faster refined way is to add a 'Curves' adjustment layer; drag a middle control point outward so the image gets lighter (or darker for refining darker areas).
After that adjustment layer, paint in the Curves' layer mask (make it black first) with a 10-20% white brush to tune in lighter areas.
This method allows you to worry less about brightening darker areas, as all is dependent on the underlying layer(s).
(c) 2006-2011 Dolphinity
B.V. / Ruud van Gaal