Programming

For programming in PHP, it  depends on the framework used, if it's osCommerce, try to follow the standards set in osCommerce, put all text strings in language files the way osCommerce does and basically just try and mimic the framework. Every script has it's own templating system so  try to utilize it.

If you're creating your own framework, would mimic whatever frameworks feel most comfortable. It is advisable  to have a config.php file that will do all preprocessing and then have each page include the config.php file at the beginning.You can created your own templating system for your own framework, but do not going to try and integrate it if you are working on a Joomla site, better to to use Joomla's templating system.

Do not to throw off the logic of whatever framework you are working in and if you are creating from scratch, try and mimic a framework that has proven to be productive and try to be consistent.