In Magento admin, (top menu) System > Configuration, (left nav) Catalog > Catalog, (main page) Frontend. Set “Use Flat Catalog Category” and “Use Flat Catalog Product” to “Yes“.
Attributes that apply to Categories and Products are stored in separate database tables depending on their dataypes. ‘Flattening’ will put all attributes in one table for Magento retrieve. This will have a positive impact on site speed especially if it has 1,000 or more products
2. Merge CSS and JS Files
3. Enable Compilation
In Magento admin, (top menu) System > Tools > Compilation, click Enable. This will take all the active scripts in Magento’s core structure and bring them to the front for faster website speed.
If updates, code modifications, extension installations are needed, Compilation needs to be disabled first. If not, there will be errors.
4. Caching Magento
When all other settings are in place and the site is ready to go live, go to System > Cache Management. Select all items, set the Action dropdown to “Enable” then hit Submit
The above settings will help increase the performance of an average Magento website. Those who are accustomed to server administration can do more. There are caching extensions that can be incorporated within Magento’s configuration file and other server tricks to speed up Magento.