• For server side programming we prefer using NodeJS/Python over PHP, so only use PHP when necessary
• Use a clean folder structure and use include to add other files. Make sure files don't get longer than 200 lines
• For reasonably sized projects, use the MVC structure
• If you are storing user data, especially passwords, you must use a framework like Laravel, because you really really shouldn't mess with storing that stuff yourself
• PHP is notorious for ugly code, so be aware of this and write your code extra clean
• Always use PHP 7.0+

This is an extension of the PHP part of this file

• Write your WordPress code along the rules of the WordPress Codex
• Write variables using underscores (snake_case), not camel-case, because WordPress does not allow camel-case, so write variables like this_is_an_example
• Don't change anything in the core files or existing plugins/themes! Use hooks, make a plugin out of it, or add it to the child theme
• Don't hardcode paths, use functions like get_stylesheet_directory_uri
• Never write MySQL queries yourself, use $wpdb
• Enqueue your stylesheets by hand, not just in the style.css file
• For your custom styles and scripts, use Webpack or Gulp
• If possible, use the tools from Roots.io