I'm battling a 10 year old library of incomplete albums, disorganized tags and folders. Here is how I am doing it.
I use the Rename, Move, and Copy Files feature and a certain directory structure. I have an "Incoming" folder with everything I haven't processed, and a "Processed" folder that is my organized, tagged library. I created two views in the Audio tree: "Incoming" and "Processed" (filter is based on file path name). What I then do is:
1. Update tags, art, and other metadata on albums in the "Incoming" view.
2. When I'm happy with the album, I will right-click and run a Move to move the album into "Processed" and rename tracks/folders to conform to my standard naming template. You can save presets, so it's pretty quick.
It adds a bit of structure to the chaos and works great.