Photoshop History palette is a great help.
Its simpler version can be found in Lightroom as well. In
order to apply it, select the Windows/Panels/History
list is to be found on the left side of Develop
menu. While you edit your photo, it records each of your
actions. If you would like to return to any previous stage,
you simply have to click on its name in the list.
It’s no problem if you have carried out a lot of actions
and you don’t remember which is that desirable previous
stage. It is enough to drag the mouse pointer over the names
and the preview as well as the editing surface above will
show that stage.
Stages that can be saved
there is a pile of editing actions made, you can save the
major ones you wish to keep as Snapshots.
Right click on any row in History
list and choose the Create Snapshot
option in the appearing list. You can even name the stage
you have saved in another window.
These then will appear above the list on the Snapshots
panel. Click on any of these names to load the
stage you wish.