How to troubleshoot issue with Audi A3 engine not starting?

My Audi A3 is having trouble starting - the engine won't turn over. What could be causing this issue and how can I troubleshoot it?

One possibility could be a dead battery. Try using jumper cables to jump start your car or replace the battery entirely. Also check the battery connections for any corrosion or looseness.

Another potential cause could be a faulty starter motor. You can test this by tapping on the starter while someone else tries to turn on the engine. If it starts up, it's likely the starter needs to be replaced.

It's also possible that there is a problem with the fuel system. Check the fuel lines and filter for blockages or leaks. If necessary, have a professional diagnose and repair any issues.