Some of the most common mistakes that new PHP developers make include the following:
1. Not using Object Oriented Programming (OOP) principles: OOP is a powerful way to organize code that allows for efficient reuse and scalability.
2. Not understanding how PHP works with databases: PHP is closely related to databases, so understanding how to use them correctly is essential for a successful project.
3. Poorly written and inefficient code: Writing code inefficiently or in a difficult way to understand can lead to bugs and other issues.
4. Not understanding security principles: Not understanding basic security principles can lead to hackers being able to exploit your code.
5. Not using the latest version of PHP: PHP is constantly being improved and updated, so it’s important to stay updated with the latest version.