What are some common pitfalls when planning and executing large PHP projects?

One common pitfall when planning and executing large PHP projects is poor code organization, leading to spaghetti code and difficulty in maintaining and scaling the project. To solve this issue, it is important to follow a proper directory structure, separate concerns using design patterns like MVC, and adhere to coding standards.

// Example of a proper directory structure for a PHP project
- project/
  - app/
    - controllers/
    - models/
    - views/
  - config/
  - public/
    - index.php
  - vendor/
  - composer.json