In this post I cover self-hosted first then WordPress or free hosted blogs.
Self-Hosted Blogs (WordPress.org)
Before you take action to optimize and speed up your blog for your readers, you have to face the music. WordPress Inspector is an excellent starting point. You can find this is the sidebar of my blog. Click on it and see this blog’s performance score. Optimization and speed is important to me. SEO helps keep the readers coming in. (both self and free hosted can benefit by running WordPress inspector. Self-hosted will have more options to use to optimize.)
Google Webmasters Tools and Page Speed insights are also excellent free resources. Can for both host types.
Consider the load you are processing on your index. Each post page may be just fine but 10 posts per page may be too much, especially if your
posts are not optimized in areas like images. If your images are 100K or more, recognize that to make a decent performance score, you’ll have to reduce their size. One way easily do this with every post is: TinyPng
Free Hosted Blogs (WordPress.com)
Without cache and SEO plugin ability, free host bloggers may have to use inventive and content based remedies. I recommend contacting WordPress.com support if your site is performing very slow.
May I suggest rethinking the size of photos you put in your posts? If you only need a width 150 px, don’t but a 600 px in and size it in WordPress. Change the size first.
Also, Rethink the server pull from your sidebar. Many people use their sidebar as a scrapbook. Think of it like a traveling King Tut exhibit that must pack up and go every day. If you leave a lot of server pull in you blog, you better hope you never get popular. This can wear on server very quickly. Remember. slowness of site loading will keep potential readers away.
Go through your Media Library once in a while. If huge photos can be shrunken, go for it. Do a search on WordPress free hosted optimization, it will yield some very helpful stuff as well!
Last, rethink how many posts you’re showing on your index. This can improve a score immediately and greatly by making it 5.
Best of luck! If you have questions, let me know.