In PHP development, what are the best practices for maintaining clean and user-friendly URLs while still accessing specific PHP files?

To maintain clean and user-friendly URLs while still accessing specific PHP files, it is recommended to use URL rewriting techniques. This can be achieved by configuring your web server to rewrite URLs to point to the appropriate PHP files behind the scenes. This allows you to have clean URLs for users while still accessing the necessary PHP files for processing.

```php
// Example of using URL rewriting in Apache's .htaccess file
RewriteEngine On
RewriteRule ^blog/([a-zA-Z0-9-]+)$ blog.php?slug=$1 [L]
```

In this example, any URL in the format "example.com/blog/some-post-title" will be rewritten internally to "example.com/blog.php?slug=some-post-title". This allows for clean and user-friendly URLs while still accessing the necessary PHP file for processing.