The windows in my house has 2.5 inch molding around the windows. I created this clip so I could clip the curtain to the molding and essentially seal the windows to prevent cold drafts. My molding is not flat so to avoid having to customize the clip for every type of molding, I tried to make it as generic as possible. I use about 6 clips per windows, 2 on each side and 2 on the bottom. The top of the curtain in the windows is on a rod so I don't try to seal that off. Hopefully this will helps cut down some cold drafts with your windows as it has mine.
If the clip is to big you can fold over your curtain when fitting it on the molding.