There are several steps that you should follow in order to improve the performance of your Drupal-based website:
First, you should enable the caching system of your Drupal application. In order to do this, login as administrator and go to the Administer -> Site Configuration -> Performance menu. In it, set the values of Caching Mode to “Normal” and Block Cache to “Enabled”. Then, click on the “Save configuration” button at the bottom of the page.
Next, you can disable all the modules/blocks that you are not actually using. To do this, go to the Administer -> Site Building -> Modules menu. Note that the enabled modules have a check in the “Enabled” column. Remove this check for all the modules you want to disable and then click on the “Save configuration” button at the bottom of the screen.
In addition, you can try reducing the content you are displaying on your front page. Too much links/images/scripts on your main page can signifficantly increase the time your website needs to load.