When you visit sites, your browser often caches pages on the site to speed up load time.
Browser caching stores webpage resource files on a local computer when a user visits a webpage, so leveraging browser caching is when you instruct browsers how their resources should be dealt with.
Things can slow down when the response from your server does not include caching headers or if resources are specified to be cached for only a short time.
Leveraging caching will load your pages much faster for repeat visitors and so will other pages that share those same resources.
The code below tells browsers what to cache and how long to "remember" it. It should be added to the top of your .htaccess file.
If images load faster, your site loads faster, period. Google notes that “…images often account for most of the downloaded bytes on a page. As a result, optimizing images can often yield some of the largest byte savings and performance improvements.”
This means that you can get some big improvements when the images on your pages can be optimized to reduce their file size without significantly impacting their visual quality.
redundant data that you can remove includes code comments and formatting, removing unused code, using shorter variable and function names, and more.
Minifying removes any unnecessary characters that are not required for the code to execute.
Gzip compression drastically reduces the size of files sent from your server when someone visits your website. This will speed things up considerably.
According to GTMetrix,
“The reason gzip works so well in a web environment is because CSS files and HTML files use a lot of repeated text and have loads of whitespace. Since gzip compresses common strings, this can reduce the size of pages and style sheets by up to 70%!”
Server response time is the amount of time it takes for a web server to respond to a request from a browser. This is a key issue to address because if your server response time is slow your pages will display slow, no matter how optimized your pages are for speed.
Google says you should reduce your server response time under 200ms. So how do you make this happen?
Your site can really slow down when you have more than one redirect from the given URL to the final landing page. This sets off a redirect loop that takes time to process.
Here are a few examples of redirects that can slow things down:
This is the exact message you’ll get from Google’s PageSpeed tool when additional network round trips are required to render the above the fold content of the page.
However, this is a common message you’ll get from Google about site speed, and addressing it can really take your page speed up a few notches.
Note: This is the hardest thing to fix for most people. There are WordPress plugins that just do it but they can make your site look like Frankenstein on every load.