Lean towards relating two tiddlers with a tag if one is {part of} the other, and towards relating them with a link if one is merely {related to} the other.

Grok TiddlyWiki

I usually think of tags in relation to a blog where they indicate a relationship as opposed to membership. This is helping me think about organisation of information. I use a few TiddlyWikis, but have just stumbled through the process.

Read: Music Love Drugs War by Geraldine Quigley ★★★★★ 📚
Beautiful book about a group of youths in 1981 in Derry in the midst of the troubles. Their difficulty in expressing themselves & sharing feelings is heart-wrenching. I raced through this.

Read: Luckenbooth by Jenni Fagan ★★★☆☆ 📚
A novel Maddox up of short stories over 100 years linked by a Edinburgh tenement. Gothic, ghosts, queer, beat, crime and more. Some seemed to flow for me better than others. Probably best read in fewer sessions than I did.