If space allows on the wall above and on both sides of the black curtain rods, extend the window covers to the roof and out of each side. Create a formal border along the top of the bay window just below the roof to make the window look bigger and taller. Install the side panels that extend out from each side to make the window look wider. Cover the real windows with curtains or blinds to control light and privacy, if desired.
If the windows do not extend to the floor, consider adding a padded window seat with cushions for comfortable black curtain rods. If the windows extend to the floor, place occasional chairs at angles near the bay window. Install the side panels and a valance on the top to make the corner look more private and cozy. Cover the windows with Roman curtains for easy ascent and descent to control light as you wish.
Hang curtains separately each window on separate curtain rods. Vertical curtain panels add definition to the independent windows of the bay window. Install second black curtain rods over the bars of the separate curtains for a loot to extend over the entire window to bring the window covering effect together.