Install a double curtain rod above the single window where you want to hang the velvet drape panel. Insert the screws into wall anchors, if necessary, to ensure that your outer curtain rod is strong enough to hold the heaviness of velvet without pulling out of the wall under the weight.
Hang a sheer panel on the inner curtain rod. A sheer panel will provide a modicum of privacy even when you have the velvet drape tied back. Choose a complementary or contrasting color to go with the drapes you've selected.
Hang the velvet drape panel on the outer curtain rod. Spread the curtain out or bunch it accordingly, so that the panel is distributed evenly on the rod.
Install a tieback hook into the wall on one side of the window. Take the decor of the room and the arrangement of the furniture into consideration when deciding which side to install the tieback hook on.
Choose a curtain tieback in a material like brocade or velvet and install it on the tieback hook to complete the look of the window.