The speed of your blog depends to a great extent, which Theme / Template you have used. You will find many free and paid templates on the Internet, but before using the template, you must read its review whether it is SEO friendly, fast loading, mobile friendly or not.
While creating a blog, choose a good template and use the same template for a long time, because changing the template again and again has an effect on the search engine ranking and it has many other risks.
2: Remove Unwanted Widgets
Whenever you upload a template to your Blogger blog, by default you will see many widgets like search box, archive, visitors count, tags, featured post etc in sidebar and footer. The more widgets you use, it will also affect your loading speed.Therefore, you should use only those widgets which are more important such as recent post, popular post, social media follow button and category.
3: Compress Images
Images take a lot of bandwidth to load, due to which the loading speed of your blog decreases. You can increase the speed of the blog by 50% just by properly optimizing or compressing the images.You will find many tools online for image compression such as CompressJPEG, ImageOptimizer, compressor.io
4: Avoid Too Many Ads
5: Use Minimum CSS and JS
6: Compress codes
You can compress the code of your blog using HTML Compressor tool. Once the code is compressed, this site will show you how much size you have saved. This site will notify you if any changes are required in your code. You can use the Code Beautifier tool to restore your compress code again.