How do I troubleshoot an oil leak in my Audi 80?

I recently noticed a puddle of oil under my Audi 80. What could be causing this and how can I fix it?

First, determine the location of the oil leak. Check for leaks around the valve cover gasket, oil pan, and oil filters. If the leak is coming from the valve cover gasket, it may need to be replaced. If the leak is coming from the oil pan, ensure that the drain plug is tight and replace the oil pan gasket if necessary. If the filter is the issue, make sure it is properly tightened. If the leak persists, it may be a sign of a more serious issue and you should take your car to a mechanic.