Does the guest win when they interact with your restaurant?
Every guest interaction is a transaction that the guest needs to win. Whether it is the purchase of goods or the time spent looking at your marketing, the guest needs to feel they got more out of the relationship than they gave.
When you send an email to your list, you need to match the value of the time you are asking the guest to take with the benefit they are receiving.
Is your email taking longer than 30 seconds to read without giving any value to the guest?
You may have an excellent open rate, but if your emails are too long, most guests won't even give it a chance; they won't see the value in giving you that much of their time.