Plugin development checklist

Checklist

Get a unique and descriptive name

Create a unique prefix for functions and classes

Create an appropriate plugin folder structure

• Keep Images in an images directory
• Keep Javascript files in a js (javascript) directory
• A lang or languages directory for pot-, po-, and mo-files.
  

Create the default plugin files with necessary content

• Php-file with the same name as the plugin ( directory name ).
• Add the header text as needed to this file
  • Plugin name
  • Language
  • Description
  • version
  • possibly links to plugin and its author
• Add an uninstall.php file to clear all traces of your plugin when being uninstalled.
  

Include a license text if needed

• Directly after the header in the plugin php-file.
  

Create activation function

• If needed, verify correct version of WP.
• Set default options so the plugin works directly after activation.
• Create the register_activation_hook() to start your activation function.
  

Create deactivation function

• Usually don't clean up to much so that a reactivation will be able to continue as when it was deactivated.
• Create the register_deactivation_hook() to start your deactivation function.
  

Code for multilingual use

• Use __('my text', 'textdomain') and the likes for all texts to be output.
• Use Poedit or similar tool to generate a pot-file and any language files (.po /.mo) for languages you support out of the box.
• Use english in your code and translate to your language.
  

Use WP-provided functions and constants to generate correct paths

• These provide proper paths to places in WP even when these are non-standard
• Also for proper paths in your plugin if necessary.