I also try to keep ACTIVE tags to a minimum but I try to keep fewer notebooks by far - only because my initial strategy for using Evernote (a notebook per project) was quickly outgrown based on the way I want to and find I'm fastest at using information...and that is where I agree with much of what is above...you will need to experiment and test things out and see how they work for you. No list will work for everyone...for instance I have a job where I am frequently traveling both in my own state to business locations as well as nationally to various cities for presentations and meetings so I have a NUMBER of tags under Where...that might not be needed for every person. I also use the Outlook Web Clipper for Work and the Gmail Web Clipper for Email to move email that is reference information into Evernote (so going on over 25K notes after about 6 solid years of use)...hence such a big project hierarchy...again would annoy some but works quite well for me.
My basic hierarchy is:
A tag by business quarter (for me it's semesters)
trip - city - event (repeat for as many as you need)...I do reuse this one if I go to an annual meeting at the same conference over multiple years)
location name (repeat for as many locations as you have in your organization as you need to travel to)
1:1 Initials of Person (repeat for as many as you need)
List each family member's name (this is primarily used for tagging photos at holidays...and as the "official" family photographer it helps me to quickly scan to see who I don't take enough pics of to make sure I capture more at our next get together)
mtg-Name Of Group (repeat for as many as you need)
prj - 0. Ongoing [Not really projects since they are ongoing maintenance activities that just need to be included in my weekly review
prj - 1. Personal
prj - 2. Work
prj - 3. Delegated
prj - 4. Watching [Used for projects not currently in my "circle of influence" but that have at least a rough tangential relationship to my team
prj - 5. Inactive Projects
prj - 6. Completed Projects Year [Repeat one per year - I have these going back to 2012]
prj - 7. Someday-Maybe
prj - 8. Cancelled Projects
Reference (and under this are a myriad of random tags that are logical to me)
I tag each project underneath each of those project headers as prj - 1. Project Name and so on. When I move something from a 0, 1, 2, 3, or even 4 to Inactive, Completed, Someday-Maybe or Cancelled I rename the tag to prj - 5.1. Project Name or similar to keep the Outlook Web Clipper from having 30 different 2. projects show up in my list of specifics. Because I use the Outlook Clipper my tags come up in a list as I start typing them so I can enter pretty quickly. If you are emailing in notes then my naming scheme gets pretty cumbersome if you don't use really short names.
Hope that's helpful - Good Luck!