Lightoom remembers just about everything you do while image editing, but if you’re tinkering a lot, the History pane can get quite tedious. In addition to History, I’ve started using the Snapshots function. When ever I get to a point where I like what I’ve done, I click the + button in the Snapshots pane, give it a number so I can remember where this adjustment fits in the order of things, and a descriptive label. Then I continue working.
As I continue experimenting with the image, I can always review the previous stages by mousing over the Snapshots title and seeing the preview in the pane above. If I want to return to that stage, I just have to click on the title itself. I could go on and wax about the virtues of non-destructive editing in general, but you already know that. The Snapshots function is a great way to take advantage of that.