Working in Photoshop, we tend to go down many avenues in a single project. The ability to try so many different things is really one of the coolest things about this program, however, despite our love for ctrl+alt+z and ctrl+shift+z, there are sometimes changes we need to make that require a bit of rummaging about in the pixels.
Now, you might be familiar with less elegant workarounds that, admittedly have become part of even my Photoshop experience, namely the duplication of layers when any major pixel work is needed. But the more this can be avoided, the better it is for your project, in terms of file size, and layer-count and complexity, but most importantly for flexibility. This is the non-destructive way to work in a Photoshop project, as dealt with in this cool post, by Adrian Taylor, on Smashing Magazine, where a number of these techniques are discussed. There are some drawbacks, especially in the use of smart objects, but otherwise, it’s a more elegant way to do things.
For a more in-depth look at some of these techniques, check out this video, from the post.