Unless you start out with the mindset to keep things organized, you will eventually end up with some cleaning up to do later on.
The clean-up might be time-consuming if you need to update the ID3 tags or it might be simple like finding album art and adding it to your music files.
Afterwards, put a check box in something non-necessary like the 'Composer' tag and put a space in it or perhaps your DJ name.
If you use Windows Media Player or the Music app (Windows 8 & 10), here’s how you can add album art to a music file and update its ID3 information without needing any extra apps.
The first thing you want to do is find album art for your music and for the sake of keeping things organized, you might want to save it all to the same folder.
When you click 'OK', i Tunes will modify all of your highlighted file's 'Composer' tags to whatever you chose and at the same time, it'll re-read and update all of your tags.
I'd practice this on a small batch of files (5 or so) before you attempt this on your entire library just so you don't make any mistakes.