Below I will list some tipps to improve the overall Magento performance of your shop:

  • Disable Mage_Reports logging for simple page views (use external analytics tools instead)
  • Disable unused (core) modules, e.g. Mage_Poll, Mage_Tag, Mage_Rss, Mage_Wishlist, Mage_XmlConnect, Find_Feed, Mage_Authorizenet

    (Pay attention to all side effects, e.g. when deactivating Mage_Wishlist the customer detail view in admin won’t work any longer in CE 1.7)

    See also my blog post about disabling the Gift Message extension.

  • Disable Magento file logging in production (or at least set up log rotating)
  • Implement block caching for header / footer / navigation bar / product lists / …
  • Use one of the latest Magento versions
  • Use proper JS/CSS minifying
  • Assure Catalog flat index is up-to-date and therewith Magento does not use EAV tables
  • Use one of the newest PHP versions (5.4 or 5.5) because of better memory management
  • Follow the performance tipps by the Magento ECG group