I started using Obsidian about a month ago. So far I've been treating it like a personal wiki. It took me a while to start really figuring out what to create, but now some of my primary subjects are technical notes (programming), ancestry, health, academic notes, etc.
I mainly feel prompted to create notes based on learned information. I might take an article found online with really interesting information, then convert it into my own words and save that as a note. The more concise I can make the note, the better. It's preferable to try and get to the main point of a subject in a few sentences or less. Doing it this way makes future me spend less time retrieving the information I need.
One shortcut that has helped me a lot is CTRL + O. It will open a promp to find a note, or create one if that doesn't exist. It's important to give your notes basic tags as well for what topics they pertain to do that you can make searching easier.
As for how much I use it, currently maybe a couple times a day, but I anticipate my usage growing as my note collection becomes larger.