If you're looking to organize your blog so that you can post about totally separate separate topics, there are several routes you can take. The easiest is to use "categories" for each topic. If you're blogging, say, about auto repairs, French cooking, and movies, then assign the appropriate category to your posts. With the "categories" widget, your readers can click on the category of their choice, and they'll get a list of your posts in that category. Simple. It's probably what most people do.
The second method is to make one post a "sticky," so it will always be visible. On that post you can have links to guide your readers to where they want to go.
The third method, and the one that requires the most work, is what I'm doing. I have various tables of contents in Pages; each consisting of several hand-assembled links. I started out with only one table of contents, but it got too big so I broke it down into separate lists, putting each in a page of its own. It takes a bit of time to maintain, but it works for me.
You could have a totally separate blog for each subject, and use the sticky first page of each to provide links to the others. Or you could put those links in a Page, possibly titled "Related Blogs" or something. But that's not what most people want.
What you can't do is use Pages as if they were junior blogs, with each Page having its own posts.