What steps can PHP beginners take to improve their understanding of script functionality and prevent common errors like variable overwriting?

To prevent common errors like variable overwriting in PHP, beginners can improve their understanding of script functionality by practicing good coding habits, such as using unique variable names and keeping track of variable scopes. They can also utilize debugging tools like error messages and print statements to identify and resolve any issues that arise.

// Example of using unique variable names to prevent overwriting
$firstVariable = "Hello";
$secondVariable = "World";

echo $firstVariable . " " . $secondVariable;