In How to Optimize Your Website's Loading Time and Performance I covered some of the basics about Page Speed and Optimization.
On top those tips -- minifying scripts and stylesheets, optimizing images, and taking advantage of caching -- there are several other tips and tricks that can help improve the performance of your website. Some of these techniques may not be suited for all types of content but where they are, you can see dramatic improvements in page speed and functionality.
You've probably seen this technique used before without even realizing it.
So, what is Lazy Loading?
It's the programming practice of loading or initializing an object only on demand.
Instead of loading all your assets as soon as a page is called, it allows you to load specific ones only when they need to be delivered to the user.
For example, if you have a large image gallery you may want to load the first ten images, but lazy load the rest. Doing so takes the weight of the additional images off your browser on page load, and when the user scrolls down or clicks a "More" link the next set of images will be displayed.
This technique is great for pages with a large amount of content. I used the picture gallery page as an example, but I have used this technique countless times on blog archive pages, or any page that has a large amount of content "below the fold".
If you want to install this functionality for images on a WordPress site, check out Lazy Load in the WordPress Plugin Repository.
Want to apply Lazy Loading to your WordPress posts themselves? Check out the Infinite Scroll plugin.
If you find yourself dealing with a lot of images, you might also want to look into the WP Smush.it plugin. Once installed, WP Smush.it will optimize your images for online viewing. It reduces the file size of your images, thus improving your loading times. No additional steps are needed: whenever you upload a new image it will automatically be optimized!
WP Smush.it can be used in conjunction with any other plugins, like Lazy Loading, or on its own.
Don't Over Do It With Plugins
I know this may sound like it goes against what I just told you, but you another thing you always needs to keep in mind is keeping things simple. Limit the amount of plugins you use.
If you use one, make sure it is efficient and provides a vital function on your WordPress website. It's very easy to get carried away with plugins, and they can really be resource hogs. I strongly encourage any website owner to keep things as simple as possible.
Tese are still only some basic starting points to optimize a website's performance. There are countless other techniques that you can use to speed up a slow site or to make an already fast site even faster.
Do your research and determine what areas of your website need improvements. From there, take it step by step, and remember to keep it simple! Good luck, and happy optimizing!