How to troubleshoot a faulty starter in a 1992 Audi 80?

My Audi 80 is having trouble starting, and I suspect it may be due to a faulty starter. Does anyone know how to troubleshoot and fix this issue?

First, check the battery and connections to make sure they are clean and tight. If those are okay, then try tapping on the starter with a hammer while a friend tries to start the car. If it starts, the starter may need to be replaced.

You can also try jumping the starter with a screwdriver. If it starts, then the solenoid may be faulty and will need to be replaced.