Once you have identified the function of your window treatment, you will need to determine the style of you windows. Consider the architecture of the windows you will be working with so you may chose an appropriate treatment.
Casement style windows look good with almost any style of window decor. The drapes can be cut to sill
or floor length as your design requires. This is the most common window style in most homes.

Georgian sash windows were often shuttered and dressed very formal in swags and tails. These windows have beautiful
proportions and you can use almost any treatment you wish. You can even dress them in simple sheer panels and they are
beautiful.

French doors that open inward will need to be dressed in shades on the frame or drapes on a hinged rod. This
will allow movement of the doors. If the doors open outward the movement will not involve the treatment.
Therefore you may dress them with curtain rails and rods. Shades can be mounted above if desired.

Loft
style, usually converted warehouses windows, are large metal framed
windows. This style window is best suited to shades or simple panels.
They are often seen with billowing sheers.

Pivot windows due to their movement, need shades attached directly to the frame. If you are not using the windows treat them to suit their proportions.

Semicircular
or round windows are usually set high in the room and are a natural
light source. Semicircular windows are also often set above front
doors. Round windows are sometimes used as light accents inset into
the backsplash above the kitchen countertops. You may leave these
windows untreated or fit them with sandblasted or stained glass if
privacy is needed.

Arched windows are elegant and beautiful even unadorned. They are wonderful fitted with custom made shutters or pull-up shades. If you wish there are many styles of draperies that may be used. For maximum light and privacy hanging paneled drapery just at the start of the curve adds the beauty and softness of fabric and a shot of color.
Victorian bays are usually tall with sash windows. They are found in historical homes.
Modern Bays are generally made up of casement windows. Treat the whole bay as a single unit when planning your window
treatment.

Once you have identified your window's architecture style you are ready to start thinking about your window treatment.
Elizabeth Dinges