Large windows cannot be treated the same way as normal sized windows. This is because large windows occupy much more space. If you were to hang curtains that you would for normal windows on them, they would look very bland.
Having large windows is a good idea, especially in the north where winters tend to get very cold, and any sunlight is good. Yet summers are very hot, and you may not want your home converted into a greenhouse.
Getting good curtain designs for large windows is the best thing here. For example, the swag curtain is one of the most popular designs for large windows, especially the long, French window type ones. They give your window a frame, but also give it a design on the top that reduces their visual height.
You can go with window coverings for large windows like panel blinds. They may be more expensive, but they are also easy to manage, and don’t need as much maintenance as do curtains.
You can opt for valences for your window. These valences can be of any shape that you like, a plain horizontal strip on the top or an inverted V shape. You can have them in a different color to the curtains or can just be differentiated by a differently colored border.
You can also put in a number of short length curtains splitting up your window into smaller frames. Going with different colored curtains is a risk, but if you are able to do a good job matching the colors it will look even better than having the same color throughout.
If you are a little brave, you could go with both blinds as well as curtains. You install mini blinds that come half way down the window so that you restrict the amount of light that comes in during the day. The curtains are to be left drawn back. They will frame the window, while the blinds provide the sunlight reduction. You can always just draw closed the curtains if you want to, or you could actually just leave them as they are, and use the blinds to provide the privacy that you need.
What you do does not depend on what has already been done. If you are able to close your eyes and visualize how you want your room to look, just follow your intuition. You’ll find that the end result is much closer to what you wanted than if you had followed other people’s advice.