How can I troubleshoot my Audi 80's engine not starting?

My Audi 80's engine is not starting and I am unsure of what the issue could be. I've checked the battery and the starter, but it still won't start. Any ideas on what could be causing this and how I can troubleshoot it?

Have you checked the fuel pump and fuel filter? If either of those are clogged or malfunctioning, it could prevent the engine from starting. I recommend checking those next.

Try checking the spark plugs and ignition coils. If either of those are faulty, it could prevent the engine from starting. You may need to replace them if they are not functioning properly.