T.F.
For starters, we have a glass enclosed shower and when you are finished with the shower, you squeegee the glass. Takes less than 5 minutes and saves a boatload of work later.
I LOVE the Comet bathroom cleaner. White spray bottle with green label. It works wonders. I spray my shower once or twice a week and leave it til the morning and there is never any scrubbing.
If you have buildup, it will take a while to break through it all but eventually you can. On any stubborn spots I use a grout brush (tile flooring dept of home depot about $2) and that is great.
Good luck