Above is a recent window treatment by Claire Schwab, who is an Alexandria, Va.-based designer and a certified window treatment consultant with more than 20 years of experience.

Window treatments dress up bay windows.

Besides picking paint colors, the one topic that consistently seems to stump many homeowners is window treatments. Claire Schwab is an Alexandria, Va.-based designer and a certified window treatment consultant with more than 20 years of experience. She offers her advice:

Q. What’s the best way to inexpensively dress a window?

A. If privacy isn’t an issue, start with the basics: panels and a pole. They are so readily available now at places like Ikea, Restoration Hardware and Pottery Barn, and they make it so easy. If you can go beyond that step, add a grass or woven shade underneath. The next layer would be adding decorative trim on the inside edges of each panel. You can add the trim yourself with a glue gun or have a dry cleaner do it for you.

Q. What are the most common window treatment mistakes you see?

A. The one I see most often is not hanging (curtain) panels high or wide enough. Other mistakes I see are: bad measuring, buying retail curtains and not pressing them before they are hung, and not having drapes that are long enough. They should at least touch the ground.

Q. What are your thoughts on tiebacks?

A. I don’t use them. I prefer the long, flowy look. And I think they are fussier-looking. But they are still selling, so someone is buying them.

Q. What’s the best treatment for a bathroom or powder room?

A. A combination of a shade or shutter for privacy with a valance for decoration.

Q. What’s the best treatment for a nursery?

A. You really have to consider room darkening, which tends to be a mother’s priority over function! For that, you really need draperies that have room-darkening lining. You can get shades or blinds with room-darkening lining, too, but the light is still going to peek through the sides. You could do room-darkening shades with stationary panels on the sides to block light from peeking in on the edges.

Q. Floor-length or windowsill-length curtains?

A. Windowsill-length went out of fashion in the ’60s.

Q. Should panels end at the floor or puddle?

A. No puddling. It’s not as clean a look, and it can collect dust. It’s much harder to maintain.

Q. What is the best fabric to use for curtains?

A. Silks are hard to beat because they hang so nicely. Then I would say a medium-weight upholstery fabric because it looks substantial. Cottons and linens wrinkle more easily and are more casual in appearance.

Q. Is there any instance in which a bare window is best?

A. No!

Q. Should all windows in a house with an open floor plan have the same treatments?

A. Not necessarily. But there needs to be one unifying element, and the easiest element is a shade. (For example: If the living room, dining room and kitchen are open to one another), the windows in each room should have the same shade. To delineate the spaces, you can add panels on the windows, using a different fabric for each room.

Q. What is your favorite style of treatment?

A. Draperies with decorative trim on the sides; full, double lining (lining and a flannel interlining, which helps them keep their shape better); and a pretty wood pole.