How to Troubleshoot Engine Starting Issues in Audi 80?

I have been experiencing issues with starting my Audi 80 lately. Sometimes the engine cranks but doesn't start, or it starts but immediately shuts off. What could be causing this and how can I troubleshoot it?

One possible reason for this issue could be a weak fuel pump which is unable to provide enough pressure to the fuel injectors. It could also be a faulty fuel filter which is clogged and not allowing enough fuel to reach the engine. Check these components and replace if necessary.