How do I troubleshoot a 403 error on my website?

Troubleshooting involves checking file and directory permissions (typically 755 for directories and 644 for files on Linux/Unix systems), verifying .htaccess file rules (if applicable) for incorrect directives, ensuring the web server user has access to the files, and reviewing server logs for more specific error messages. Also, check if any security plugins or firewalls are blocking access.