Hold your sconce next to your window to determine the best place for it. For best results in curtain draping, set the sconce between 3 and 4 inches over the top of the window and between 1 and 2 inches from the side of the window.
Use measuring tape and jot down information once you determine the best spot, documenting the exact distance from the window, on the top and on the side. Mark the ideal spot lightly with a pencil.
Use your measurements to place a mark opposite the first mark on the other side of the window. If your first mark is 2 inches above the window and 1 inch to the left of the window, then your second mark should be 2 inches above the window and 1 inch to the right of the window.
Place a wall sconce on the left side of the window, over your marked spot. Use a screwdriver to secure it with mounting screws. Repeat this step on the right side of the window.
Use a level on each sconce to make sure it is even on each side. Readjust the placement of the curtain sconces if necessary.