The space besides a window is usually underestimated and sometimes even left free. Although we, practical people, need to use it somehow. There are some ways to do that. For example you can make a window seat under the window and bookshelves from both sides of it. Of course you can also use the space above it for additional shelves. The space below the window can become a working place with a desk. Instead of bookshelves you can make closets from both sides of the window. These and some other ideas you can check out on the pictures below. Enjoy!