Many useful hooks for wordpress

http://wordpress.stackexchange.com/questions/1567/best-collection-of-code-for-your-functions-php-file?page=2&tab=votes#tab-top

How to Customize the WordPress Admin Area

http://sixrevisions.com/wordpress/how-to-customize-the-wordpress-admin-area/

PHP Programming tricks

http://www.gauravkgupta.com/development/20-tips-need-learn-become-better-php-programmer/

How to do URL Re-writing in PHP with Simple htaccess Modify

http://techniblogic.com/how-to-do-url-re-writing-in-php-with-simple-htaccess-modify/#

Are You Setting Up WordPress For SEO Success?

https://moz.com/blog/setup-wordpress-for-seo-success

Easy Deployment of PHP Applications with Deployer

http://www.sitepoint.com/deploying-php-applications-with-deployer/

Social Logins in PHP with HybridAuth

http://www.sitepoint.com/social-logins-php-hybridauth/