Valentine's Day campaign should be started a few days before the holiday so that the recipients have time to choose a gift, make an order and receive it. On February 14 it will be too late to sell.
Compose some kind of cozy valentine's day email marketing subject lines. And try to create something personal in your valentine's day email signature.
If you want your subscribers to catch sight of your campaign among hundreds of others, take a closer look at examples of promos from famous brands.