There are a lot of tweaks and tips that you can implement to increase the performance of your Drupal website. This article covers most of the key modules in Drupal and by configuring these modules and settings you can easily bring some good changes to your Drupal site.
Wise Planning While Installing Module
There are many modules available for a Drupal site, and the best thing you can do before installing a module is to understand your requirement and plan accordingly. Try to figure out what each module can do and its possibilities. Then decide whether that module can serve your purpose. Some modules does not come with an uninstall option, so be wise while selecting one. Try the module on dev environment before implementing it into your Drupal site.
Updates for Drupal core and related modules are released regularly. Each update comes with a new set of added features. It is advisable to test these new features before implementing them. This will give you a good idea what all changes are there in the new module. If you find it worthy for your site, make use of it.
Alternative PHP Cache (APC)
APC is PHP based OP code cache. If you have decent skills in working with PHP, this can offer you a performance boost while using Drupal. It is a good application that can be used for better performance and results.
Drupal 6 and Drupal 7 supports Memcache. The main advantage of Memcache is that it offers a fantastic caching system. This enables you to save complex PHP modules or MySQL queries and allows storing all cache tables in memory. Finally, this can improve the performance of yours site.
Varnish is associated when your site has anonymous users reversing proxy cache. It enables you to save lot of server load. Setting up Varnish may seem slightly complex for the first time. Follow the Drupal tutorials focusing Varnish to set it up properly.