Traditional cleaning at 2nd storey height with a pole is really quite a skill, and would take a lot of practice.
The alternative is to use a water fed pole system. The basic principle is to use water that has been purified & de-ionised to remove any dissolved minerals, pumped up the pole, and onto the window. A brush is used at the top of the pole to agitate the dirt, and you simply scrub - rinse and walk away.
The windows dry streak free all by themselves!
For really dirty windows you can use a propane powered on demand water heater (Campervan or RV heaters are perfect) and the hot water works even better. For greasy windows, a 500:1 mix of isopronoyl alcohol helps, and doesn't affect the finish.
A DIY setup can cost less than $1000 and has huge earning potential,.. as ultra-lightweight poles are now being produced that reach windows 60' high and above!
There's loads of info on another forum I'm on,.. but its probably rude to post a link. PM me if you want more info.