How Can I Determine the Cause of a Non-Starting Engine in the Audi 80?

I have a 1995 Audi 80 that won't start. The battery is fine and all the lights and electronics are working, but the engine won't turn over. What are some possible causes and how should I troubleshoot them?

One common cause of a non-starting engine in the Audi 80 is a faulty fuel pump. Check to see if you can hear the pump buzzing when you turn the key to the ON position. If there is no sound, the pump may need to be replaced.