You will have to make a fuss of Libras at the St. Valentine's Day, they won't mind. Flowers for this holiday is a necessary detail! Then graceful souvenirs, rings and other adornments, knick-knackery would be to the point. Cover this day by aureole of romance. And the most important - say how you adore your beloved, that he/she for you is and will be the only unique one.
Libra gravitates towards society and takes interest in others more than him/herself. Gift to them something like a photo album, directory, book for visiting cards, notebook….
A present for Libras should be beautiful, but not flashy, loud… A graceful album on architecture, sculpture, painting would be taken by Libras perfectly. A picture or elegant statuette, which can decorate a room, would be also to their liking.
Libras have ability to softly stress their good taste, so any classic - in music or literature, would be relevant.
By the way, for Libras wrapping, as well as the way you are going to give