What debugging techniques can be employed to identify the root cause of the issue with file uploads in PHP?

Issue: The file uploads in PHP might be failing due to incorrect file permissions, incorrect PHP configuration settings, or issues with the file upload form itself. To solve this issue, you can start by checking the file permissions of the upload directory, ensuring that it is writable by the PHP process. Next, check the PHP configuration settings related to file uploads, such as `upload_max_filesize`, `post_max_size`, and `max_execution_time`. Finally, ensure that the file upload form has the correct enctype attribute set to `multipart/form-data`.

<form action="upload.php" method="post" enctype="multipart/form-data">
    <input type="file" name="file">
    <input type="submit" value="Upload">
</form>