Hi Ashley
This is pretty much normal on first cleans.
Do you go round and clean all the frames first then after giving them a few minutes to drip and run off go back round the house again and do the glass?
It takes longer but it does a better job.
Tell the customer it can take 2 or 3 cleans to get them up to standard(it can be done in one but needs lots of time and rinsing).
The one with the cloudy residue check that the frames are not "chalky" that is the plastic breaking down.
If you rub the frame with your finger and it comes back white and dusty you will have trouble with them they sometimes come O.K. with regular cleaning but not all windows suit WFP unfortunately.
Take special care with windows like this

With double top openers - if you wash down the middle of the top openers it's likely you will get runs down the middle of the bottom pane after.
Good luck - Stick at it it's hell at first

G.