In a few 'Ask Deb Nelson' articles, I have had questions about window treatments. Every window is very different and will likely need it's own assessment for the best type of covering to use. I always like roman shades, but in some traditional, classic homes a full length drapery panel is a better look. I always like a drapery with a pleat on a rod and ring, I think it adds more detail to the drapery but typically is custom made, so you need to invest a little more. In the window treatment above, I like that it shows the combination of a drapery and a blind. This is also something you can do if you want to add a more layered look and use the blinds for privacy rather than closing the drapery. You can also notice the rod is hung higher than the window and it's wider than the window frame. There are many things to consider in regards to the hardware; from exactly where and how it's hung, to how it functions with the drapery.
There are many places to buy pre-made, flat panel drapery, this means you don't have the pleats on the header of the drapery, but you can save money if you can get the correct length and width of panels. In terms of the fabric choice, you can add a lot of detail with a patterned fabric, but if you're not sure what to do, a solid linen or cotton fabric that coordinates with the wall colour (like the room below) is usually a safe bet.
Here is a look again at a custom drapery:
Image source: Lonny magazine
Style of Header
You can purchase pre-made, flat drapery panels:
Image source: Pottery Barn
Hardware is also important to think about, this is an antique brass rod with the ball finial. There are many finishes available, so the colour choice depends on what you prefer and the other accents in the room.
Image source: Restoration Hardware