A pelmet can be formal or contempory but either way it can add a luxury look to your blinds.
A very underused style. A contrasting trim can be attached to the bottom of the blind.
A blind can be edged on each side and / or the bottom in a contrast fabric to create a border around the main fabric.
Having cushions spread over your sofas or bed that match the fabric in the curtains never fails to impress and add a completeness to any room.
Bed throws, pillow cases are just two examples of bedding that can be coordinated or constrasted to your curtains.
Table runers can also be coordinated to your other soft furnishings, including curtains.