If your are experiencing strange behior, e.g. changes to a template are not being displayed on the page, then all caches should be cleared, as follows:

1. Flushing the Drupal cache (click the upper left icon in the Admin Menu for cache flushing options ... very convenient).

2. If that doesn't work, try clearing your browser's cache.

3. As a last resort, try adding a bogus query to the url.  If it is being cached by a proxy then this should refresh the source, for example:  www.example.com/somepath?refresh=1.

4. Caching problems can sometimes be unbelievable elusive.  There are times when you will clear all caches, and for some reason, cached results continue to be displayed.  One rule of thumb is to then clear the caches again, then check the results, several times over.  If you still suspect that cached results are being displayed, move the Drupal installation to another server, as that will typically enable you to determine if the issues is related to caching.