Fill a spray bottle with a 50/50 solution of Dawn dish soap and vinegar. Spray it on the hard water stains and let it work. If they are tougher stains, you may have to scrub with a plastic scrubbie!
Hi Charlene. I'm Cindy. Our old house had hard water too. The shower glass doors always looked cloudy. I found Scrubbing Bubbles (with the blue lid) worked very good. Spray it on the surface and it will foam. Let it set and do it's thing for at least 20 minutes. Then wipe with damp clean cloth. I was very happy with the results. It made those glass doors sparkle.
Comet and a scrubby
Charlene: I like Lime Away and a scrubby. Then! Always use a squeegee after every shower -- no excuses.
Oven cleaner works really well. But make sure well vented