Gazza,
On first cleans, go overboard and do lots of scrubbing and rinsing.
On subsequent cleans, wash the top frame, scrub the glass ONCE, rince ONCE.
Practice on your own windows; do some really fast and see how they turn out.
When Wor Lass makes me clean our windows, I do them as fast as I can and they generally turn out great; despite my oxidised paint on the upstairs windows.
I will also wet a window and then 'nip' the hose to stop the water flow, using a backpack, to conserve water and scrub a window if it's got difficult to remove bird poo on it.
Then release the hose, wash the window again and rinse.