I take a lot of photos but sometimes I don't have time to edit all of them. I tend to forget which photos are "done" in regards to edits, and which still needs work. Is there a way in Lightroom to somehow tag what photos are done and what photos still need work?
I usually use color labels for that.
There are shortcuts for that when you have only one photo selected:
You can add a red label by pressing 6, a yellow label by pressing 7, a green label by pressing 8, and a blue label by pressing 9.
If you need to apply a color label to multiple photos, select them all then right-click, choose Set color label and the color you want (the same is available via the menu).
Which color means what is your own choice, of course. You can also filter your photos based on these color labels.
You can filter on the ones that have not been edited "Unedited photos only".
If you want finer granularity (i.e., between edited but not final vs. final), you'll have to do that manually by designating some other property to signify "final" (e.g., a keyword "final", or specific color tag, or even a flagged status -- whatever you're not using for something else), or create a collection of all the photos and remove them as you finalize them, or...