Gummi Pflege is good for the soft rubber seals.
http://lmgtfy.com/?q=Gummi+Pflege
My right hand side rear window used to squeak/rattle a while ago and I found that by tapping the window button down to drop it a couple of mm sorted it. Now I have all 4 windows fully up and all is fine. I think weather/temperature is a real factor.