scrub
scrub
scrub
rinse
rinse
rinse
Other than those simple words, make sure you clean all the frame on the first clean. Start upstairs all the way round, then back to do downstairs all the way round. Once you have done this, go back to the first window upstairs and rinse just the glass all the way round, then do the same downstairs all the way round (if that makes sense)
Then next time you clean that house (I assume 4 weeks later) the frames will just need a quick rinse and the windows will nt spot (just remember to rinse well) and you only have to go round once.
I always go round to do a second rinse on first cleans. It takes twice the time, but it makes a good job great.
Hope this helps...