How to diagnose and fix a shaking steering wheel in an Audi 80?

I've noticed that my Audi 80's steering wheel shakes when I reach high speeds on the highway. It also doesn't seem to handle as smoothly as it used to. What could be causing this issue and how can I fix it?

It is possible that your tires are unbalanced, causing the shaking sensation in your steering wheel. I recommend taking your car to a mechanic and having them check your tire balance and rotate your tires if needed.