Update your core_config_data table to edit the two records for web/unsecure/base_url and web/secure/base_url
Delete the contents of WEBROOT/var/cache
Update / edit any .htaccess domain redirects you may have added
Restart Apache
Make sure Apache has write permissions to WEBROOT/var
If you created a new DB, ensure that the WEBROOT/app/etc/local.xml is pointing to it.
If you’re using Chrome, clear your browser cache! (Chrome caches 301s)