Knowing how to improve your website's performance is important. We use tools like P3 Profiler, Yslow, Pagespeed, and WebPageTest.org to diagnose poor Web page performance. For more information on using tools to determine Website slowness, see Website speed tests
It's quite possible that your website is slow because of one of the five issues below. Check them out, and see how they relate to your Website.
Big images are probably the number one cause of slow loading pages. Most image creation software has image compression options. There are also online tools, such as Smushit by Yahoo®! that can help you compress large images. You should make sure that each image on your website is optimized for the Web. Also, resize images to fit the width and height you want them to display on your page. We often see people upload giant 2000-plus pixels-wide images they snapped with their digital cameras and then use the width and height parameters to shrink them, like this
height="300". Don't do that. If you say width="500" height="300" in your img tag, the image should be optimized and 500x300 pixels.
If you're a WordPress user, there are a number of plugins you can check out. We've seen caching plugins affect performance both positively and negatively on customer Websites and it's largely dependent upon the traffic, and how dynamic the Website is. Popular choices for WordPress are WP Super Cache, W3 Total Cache, Batcache and Tribe Object Cache. These plugins offer various page, database and browser cache features. Try each one out (one at a time, not all at once) and see what works best for you.
mod_pagespeedto help automate this for your Website. For more information, see Which mod_pagespeed functions do you support? Also be wary of how many third-party domains you're using. Too many social buttons cause problems. If you use WordPress, you might want to check out the WordPress plugin Lazy Social Buttons.