First and foremost offer good customer service. The customer is not always right, but they should always be respected and valued. So, make sure that your customers know they are important to you, and that you want to meet their needs. If they know this, they will be more forgiving, and they will be more willing to stay loyal to you and help you meet their needs by informing you of what those needs are.
Another great way to meet customer needs is to find out exactly what it is that your customers expect from you, and how they want their needs met. You can do this by issuing customer surveys. Have customers do a small three question survey with room for comment as they check out, or by mail, etc. you can attach some sort of incentive to it. This will give you a clear idea of what your customers want, and what areas you could improve on. Surveys are a marketing campaign of sorts, they get your name out there, and they help people know you care.
Another way to meet customer needs through your marketing campaign is to make sure your customers are aware of how you will deal with their complaints. Mention your methods of dealing with complaints in the campaign. For example, say "If you are not satisfied you get 100% of your money back." This is a marketing campaign that has proven very effective because people do not feel risk, and thus are more open to purchasing something.
Another great marketing campaign that can help you to meet customer needs is through offering repeat business cards. These are like punch cards where they get incentive for coming in, buy however many, get however many free. This helps you identify repeat customers at the check out, and gives your employees a chance to ask them if there is any sort of changes they would like to see made to your level of service,