- Your WordPress database is overloaded: too many saved revisions, tables not optimized, edit post locks, etc. I would recommend you look at the WP CleanFix plugin – http://wordpress.org/extend/plugins/wp-cleanfix/ It is a management tool to check, repair, fix and optimize your WordPress blog.

- You have too many WordPress plugins and everything is slow. Only use plugins that are absolutely necessary and use often. Disable and delete the ones not being used or needed.

-Your internet browser (Safari, Firefox, Chrome, Internet Explorer, etc.) has a full cache, clear your browser cache, for instructions follow – http://www.wikihow.com/Clear-Your-Browser%27s-Cache

- Increase your PHP Memory limit. You can directly increase the PHP Memory Limit in php.ini, scroll to the line memory_limit and increase it to 256M for normal WP single site, or 512M for WPMS. Remember to restart the service for changes to take affect. I would also recommend increasing the limit in WordPress’s wp-config.php by adding this line define(‘WP_MEMORY_LIMIT’, ’512M’);

- If all else fails, post via e-mail or desktop software that uses Remote Publishing. Enable the WordPress, Movable Type, MetaWeblog and Blogger XML-RPC publishing protocols from your WordPress Writing Setting in your Dashboard. This bypasses the issue completely.