How to troubleshoot starting issues on an Audi 80?

I recently purchased a used Audi 80 and have been having trouble with starting it. Sometimes it starts without a problem, but other times it just won't turn over. I have checked the battery and it seems to be fine. What else could be causing this issue?

First, try checking the starter motor and the starter solenoid. They can become worn out over time and may need to be replaced. Additionally, check all the connections and wiring related to the starter system. Loose or corroded connections can also cause starting issues.