make a list of all your mods/cc!
i just did this the other day in preparation to update, and it's such a life saver, idk why i haven't done it before.
make a list – written down, on a doc or spreadsheet, whatever – of your mods. include the name and link to download, a short description, and requirements (other mods, dlcs) and when it was last updated/compatible. i also included the purpose of it and the creator but those aren't as important. if you list cc, i would also include pictures of the cc! either from the site or the in-game thumbnail so you can see what you're talking about.
it's a bit of a time-consuming pita if you have a lot, but it'll be so helpful! you can easily see how outdated a mod is, go back to the download page, find the names of your mods, figure out what mod is doing what.. might even be helpful in finding broken mods! :]
and of course it's great for backing up stuff, in case you somehow lose all your mods you can find them all in one place. (of course do make backups of your mod folders!)