Fill a spray bottle with a 50/50 solution of Dawn dish soap and vinegar. Spray it on the shower doors and let it work. If they are tough stains, you may have to scrub with a plastic scrubbie!
Elinda: Ann's answer was good --- altho I would add that once the doors are clean, ALWAYS use a squeegee after a shower. It really helps!
Lysol Power BathroomCleaner in the blue spray bottle is great for removing soap scum. Scrub with a power scrubber, magic eraser, or scrub daddy.
Wet & Forget Shower for weekly maintenance to prevent having to scrub in the future, but not safe for marble.
In doing this, mine looks like new without any water spots. You can also squeegee after each shower to cut back issues.
Thank I will try