Not everyone has access to fast Internet. In many developing countries, Internet is provided through slow satellite links. We managed to improve access to Joomla sites dramatically in terms of speed by using the following settings and guidelines:
Step 1: Enable the cache option in global configuration. Please be aware: with this option enabled, you may not see the changes you have made to your site immediately. And that is a bit the point of caching a site, so that the browser does not need to process information all the time.
Step 2: Enable GZIP Compression in Global Configuration. We tested access to our Joomla sites with and without this option enabled (using satellite internet links in Afghanistan), and it makes a big difference. I would not worry too much about this if your audience is in the US or Europe with fast internet, but for sites that reach out to people in developing countries or areas with slower internet connections, we recommend that you use the GZIP option. You can see our GZIP tutorial here.
Step 3: Minimize the number of components and modules you use. The more extensions you use, the more information needs to be exchanged which slows down your site. We always install a new site without the sample data to avoid modules we do not need (polls, banners, etc).
Step 4: An obvious solution to improve the speed of your website is to limit the size of images. It really makes no sense to use a 800 KB image in a header if you can compress an image to 80 KB with the same image quality. You can also use PNG instead of the larger JPG format for images.
Step 5: Avoid modules and plug ins that read information from other sites, such as world clocks or RSS feeds. They connect to other sites and this costs time.
Step 6: Find a good host that supports GZIP Compression and that has fair use policies for its shared hosting accounts. Some hosts oversell the capacity of their servers. We do recommend www.siteground.com which has been our preferred host since 2007.
Step 7: Avoid templates with many images. The more images you need to load, the slower the page will be loaded.
Step 8: Optimize the Joomla tables. This option has not dramatically increased the performance of our sites, but you may want to look into this if you have long waiting times for queries.
Step 9: Use a free online Web Page Analyzer to find out how you can optimize the site. Web Page Analyzer is a free web page analysis tool that calculates page size, composition, and download times. It gives speed recommendations based on best practices for usability, HCI, and website optimization.
Step 10: Keep the Joomla version up-to-date, not only for security, but also for optimization reasons.