Window treatments are like makeup; we don’t “need” them, but they sure do dress up a room! That being said, they also can seriously date a room.
Window treatment styles have really simplified in the last decade. One problem that has created for many of us is that we spent A LOT of money not so long ago on custom treatments. Because of that expenditure, many people hire someone like me to work around them, which results in an end that is less than the customer had imagined. My fee could have been spent on new curtains and they would. have been far more satisfied. Yup, I may have just lost a few there, but I am willing to sacrifice for the sake of design.
The general rule these days is pretty much the simpler the better. Roman shades or floor length (& really touching the floor, not a little off-it makes a huge difference) drapes are the staples today. They are being hung higher & wider than the window, so as to not lose light and accentuate the hight of the room.
Apartment Therapy has a great graphic to help you with hanging:
Are you looking for some “pinspiration”? Here’s a board of some treatments I really like!