Use email marketing and social media marketing to draw in diners on days when the restaurant is not usually full. Offer special promotions on menu items, let diners know about time-limited offers or a special dessert which the restaurant will only be offered on Tuesdays, send out coupons or make your own sale offers and more. Time messages to go out right before meal times so diners will be hungry when they receive the message. Text messages are especially effective at filling seats because, unlike emails, they are almost always opened and are usually read within five minutes of being received.