Do you always have this question in mind that how to promote the store and keep our business financially strong in the upcoming year? To accomplish this mission, you must have jotted down various marketing tactics in order to keep your customers coming to your store. Email marketing is one of them. Whether you want to stay in touch with your existing clients or want a more potential customer to pour into your online store, email marketing is still one of the most effective ways. Not to forget, your email subject lines play a vital role.