If budget allows, get a small vanity or chest to put in the corner so you can store all your supplies in it instead of on the window ledge. I would find some art to put on the wall at each end, either one large piece or two smaller ones to hang together. Hang curtains if you prefer to dress up the windows further.

BeverlyFLADeziner has it right. That is a strange looking window opening - as if someone decided to reduce the window size after the opening was done…. Cover the two blank sides with nice full drapes as in her photo.

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