How to troubleshoot an Audi engine not starting?

I recently tried starting my Audi and the engine won't turn over. No check engine light or warning indicators are on. What could be the cause and how can I fix it?

Check for any loose connections in the battery and the starter motor. You may need to clean or replace the terminals. Also, make sure your fuel pump is functioning properly.

It could also be a problem with the ignition switch or the starter solenoid. Have these components checked and replaced if necessary.