Three ways:
1. RainX - apply on the front windows & side mirrors, wait until haze, wipe off cleanly. This needs a bit of effort but after that water repels better. DO NOT APPLY ON WINDSCREEN.
2. Chemical Guys HydroView - can apply on any glass surface including front windscreen, same thing, if it hazes, wipe it off thoroughly, water repel will come when it's raining.
3. Glaco - I don't know which version to use, the effects aren't bad also. I think can use on front windscreen.
This 'unable' to see is due to your side window untreated, you can see water sticking to the surface, probably due to road grime & long use under weather, same for side mirror. The dirt is holding the water there and refusing to drain off. I'd get a piece of used claybar and clay the mirrors/windows first before applying if possible.
Currently I apply (1) on my shower screens at home, and using (2) on all my car windows. I practically drive without using wipers during rain.
Take note: none of the options above lasts forever, so top up and re-application is necessary over time.