Do you have any pics of the window/room where your curtains are going?

Curtain panels look best when the top of the panels are just under the crown molding and allow for a small (1/2") break at the floor, allowing for the drapery hardware. Also, to let in the most light, they should not cover the window glass, and extend beyond the window casing on each side. For the best fullness, the width should be at least 1 1/2 times the window width. Sheer fabrics should be 3 times the width.

If you already have the curtains and they are at a finished length/width, you may have to alter the placement to achieve a pleasing look. If you are having them custom made, then your fabricator will probably advise you on how best to dress the window and how much fabric you need.