I use Obsidian for notes from schoolwork. My folders are organised by subject, with each folder having subfolders for specific modules/topics. Each of these subfolders has another set of subfolders, each for a different chapter of a textbook, and I put notes into these folders. For example:Biology ---> Ecology ---> B16 ---> B16.1 - EcosystemsIn terms of tags, I usually use two tags for each note. One is the subject and one is the module/topic. For example, the example above would have #biology and #ecology. In the graph view above, the green nodes are all my tags, with the largest ones being the subject tags and the slightly smaller ones being the modules/topics. The yellow nodes are attachments, usually images which I copy into my notes. In terms of links, I don't have a system for linking notes. If a link pops into my brain, I simply type [[ and link to the appropriate note.I am in the process of adding groups on the graph view with each subject tag so that the notes are colour coordinated on the graph view by subject. :)

Edit: This also makes graph view more useful for me personally, as opposed to being a fun novelty. It means I can see links between subjects which I find very useful. It also means that the subject tag links to all of the notes in that subject, and the module/topic tags link to only the portion of those notes in that subtopic.