Here on booklikes we can use shelves to make broad categories of books and then tags to specifically identify different aspects of a book (the shelf titles are also used as tags.) I have a lot of different kinds of books on my shelves but I mainly review mysteries so here's how I use tags and what they mean. The more I review, the more I'll use tags I think. I know people want to find just what they want to find without wading through a bunch of junk so this should make it easier to find what a person is looking for.
Old Masters-This tag means I think of this author as a true master of the genre, someone who's writing helps define what a mystery is, and they've probably been writing prolifically for years. This would include people like Agatha Christie, Ngaio Marsh and Dorothy Sayers among others.
From the bookshelf-I have bookshelves that are full to overflowing as I'm sure many of you do. Sometimes I just go find something randomly that I haven't read before that looks intriguing. These are usually books from the 70's or older. I've rarely been disappointed with my choices.
Kindle Freebie-Every Kindle owner probably does it. We see freebies and we get them whether we intend to read them any time soon or not. I feel like a hoarder with them sometimes because I have several thousand and have read very few. So once a week or so I have started randomly picking a freebie and I've found most of them to be quite pleasant reads!
Genre and sub-genre tags-Most of my reviews are mysteries but not all so I definitely want to tag the genre. But in my mysteries there are distinct sub-genres. Most mystery readers have their favorites so it's nice to know what you are getting into. The majority of mine are cozy but I also like police procedurales, quirky, female PI, etc.These just further subdivide the genre of mystery.
French-I'm obsessed with all things French so if a mystery has any relationship to France at all I'm probably going to read it.
Some specific author tags-Some authors are just so important to me that I tag them so I or any reader on booklikes can find them easily. Right now there are two. Barbara Michaels and Agatha Christie. I'm sure there will be more as I keep reviewing.
1st in a series, 2nd in a series, etc-Pretty self-explanatory. Personally, I like to start at the beginning of a series and read to the end. I don't prefer to run willy-nilly through a series. It doesn't always work that I can go beginning to end but it's what I prefer. My sister disagrees with me on this but other than this one quirk, she's a great sister!
Geographic tags-I like to tag by state if not by region or city. I know sometimes I'm looking for a story set in a certain location and I find this quite helpful.