Categories are for broad, general sections of your site, whereas tags are for the more specific details. Let's look at it in the context of a book blog:
Most book blogs have general sections like this:
- Book Reviews
- Discussions
- Giveaways
- Guest Posts
- Interviews
- Memes
You may have more or less, but this gives you a general idea. All these sections would be your categories. So let's look at a book review:
Your book review would be in the "Book Reviews" category. But what about the tags? For those, you'd break down the specifics of the book/review itself. This usually includes:
- Book title
- Author name
- Series name
- List of genres
- Common themes throughout the book
- Your star rating
Let's use Harry Potter as an example. My tags would be:
- Harry Potter and the Sorcerer's Stone
- J.K. Rowling
- Harry Potter series
- Fantasy
- Friendship
- Wizards
- Boarding School
- Magic
- Adventure
- 5 Stars