I have also found that dryer sheets work well. (The sheets you put in the dryer to eliminate static cling) I've no idea at all why it works, but it does.
Spray with Flash with added bleach, the orange one. Scrub with a micro fibre cloth, wipe dry. Then spray again with WD40 and wipe off. It creates a protective layer and works great for me. If your shower glass is clear like mine you are going to get a slight cloudy effect from the WD40 but it's better than limey streaks that wont clean off