Site speed has generally been more of an after thought to most people, but now it needs to be front and center in your development cycle.
By default Joomla applications work quite fast. For big sites, however, optimization is necessary because if not maintained well the site can start working slower than it used to.
1, How To Optimize Joomla CMS Images for Search Engines
help Optimize your Joomla CMS Images for Search Engines and image searches getting higher rankings.
2, Activate Joomla Cache
Enabling cache will increase the overall performance of your Joomla application. You can enable caching from your Joomla admin area > Site > Global Configuration > System. At the right side of the System page, under Cache Settings, next to Cache you should select Yes. Then click Save at the top right menu to enable caching for your Joomla :)
3, Gzip and Compression
Activation of inbuilt Gzip and Cache system does speed up the Joomla site.
4, Minification of CSS / JS files
Optimize CSS / JS files to remove the white spaces or comments (which decreases the size of css / js files by 50%).
5, Disable/remove all components/modules/plugins that you are not really using
6, Reduce the number of articles on the front page.
7, Don’t use statistics or logging – use Google Analytics.
The native logging and statistics in Joomla and those offered by extensions are very resource intensive. By disabling them you will gain performance.
8, Don’t use bridges
These are brides to other CMS systems like OpenRealty or Gallery2. This will slow down your site.
9, Optimize your server for php & mysql
Talk to your host and tell them you are using Joomla which is heavy on php and mysql resources. Ask them to optimize your site for this. There are several settings that can improve the speed of your site which mostly equate to allocating more memory on the server to php & mysql. You may have issues if you are using shared hosting, but it doesn’t hurt to ask.
10, Design most of your site in HTML
As much as possible try to design your site using HTML. You can create great designs by just using HTML code. Use tables, CSS Styles and simple fonts to design your site. Minimize the use of animated gifs, Flash, bulky images etc.