Ask for e-mail addresses at the point of sale.
If customers are purchasing from you once, and you do a good job, there’s a high likelihood they’ll purchase from you again. 

Tell them they will be notified about discounts on certain or special items, exclusive e-mail-only specials and advanced notice of sales by signing up for your mailing list, either online or in person.

 Make Certain you ask,  get their permission then send to them at the level of permission they gave you.  If your guest said it's ok to e-mail once a day too tell them about lunch specials.  Then go ahead.

But if you only have permission to send an e-mail twice a month you should think long and hard about sending a daily e-mail to this customer.  They may start to think of you as a spammer.

 If your uncertain how to make this work for you please call one of our experts and get your questions answered.