We have a tub/shower area that has ceramic tile on the walls and has a small glass block window. Over the years that glass block window has been a big frustration to me because it always look dirty with water spots. This homemade cleaner has been the best thing so far on that window and has really kept water spots from forming. I've also found that the ceramic tile can be cleaned super quickly now with a spritz of my vinegar/water cleaner because once again, mineral spots are not building up.
I don't have a shower with glass doors to try this on, but I think it would work well on that type of shower too based on the positive experience I've had with it so far.
This spray is a mixture of water, hydrogen peroxide, rubbing alcohol, dish soap,and a dishwasher rinse aid. (You can click the link below to read more and get the complete recipe). After you take a shower, you just spray the mixture on the walls of the shower area the same way as you would use a store bought daily shower cleaner.