like has been said just need practice as much as you can,use fairy and put a little more water on window until you can squeeqee properly,dont try to rush the job else you will make mistakes,if your squeeqee starts slowing down on the window you will then get a streak,iv always found with a new squeegee rubber that it takes a few windows to brake it in if it hot aswell,try using pulex rubber soft,unger are crap