How can I troubleshoot a non-starting Audi 80?

I have a 2002 Audi 80 and it won't start. The battery seems to be fine, but when I turn the key, nothing happens. What could be causing this and how can I fix it?

Try checking the ignition switch and starter solenoid. If they're faulty, they may be preventing the car from starting.

Check the fuel system for any clogs or issues. It's possible that the fuel pump or filter may need to be replaced.

Make sure all the necessary fluids (oil, coolant, etc.) are at the correct levels and top them off if needed.