In a recent blog post, I discussed the importance of seeking out and responding to customer reviews on sites like Yelp. Getting this kind of feedback on a regular basis is critically important, and can help stave off real disasters.
You might also want to survey your customers yourself from time to time to get their impressions about your restaurant, food, and service. For a few ideas about questions you might want to ask them, check out this post from restaurant industry professional community and social media company FohBoh: "Top 15 questions to ask your restaurant visitors". It should get your wheels turning about what feedback you could use to really ramp things up and help ensure a great year!