Holdbacks
A holdback keeps the curtain clear of the glass when it is open, which lets in more daylight and gives the drawn curtain a deliberate shape rather than a slumped one.
Position is the decision. Higher up, the curtain sweeps into a tall curve. Lower down, it drapes more softly and covers more of the frame. Many people start around two thirds of the drop and adjust by eye.
Let the finish follow the curtain pole rather than compete with it.