Valentine's Day is a field day for marketers since it is one day when every boy and girl manages to buy something or the other for their partners and if you market your products according to their needs, not only will you sales go up, your brand name also goes up.
It is always advisable to start your promotion at the beginning of February so that customers have an idea about what is on offer before hand and can plan accordingly.
Also, it is a good idea to donate time to charity and make a point of talking about it for most people will also be interested in you because of your philanthropic ways.