If you are through your initial product development phase and are already working with customers, whether its launch or in a pilot, superior customer service is vital. You need to differentiate yourself from other providers and providing great, consistent customer service is a good way of doing so. Some best practices:
Quick Response: This will differ on a company level, but generally the faster you respond the better. Even if you do not have an answer at the exact moment you should acknowledge the issue and let the customer know you are looking into it. Best thing to do is get on the phone with them. Why? Most customers are not used to this kind of service and will be really touched–you need to make them feel loved.
Learn to say no: At a startup many customers will ask for several custom features that are not core to your offering. While it is important to hear them out, if the features are not core and may lead to distractions for your team you need to be able to say no. Do not be afraid. Many customers will appreciate the honesty and that you are focused on what you do well.
Culture: Lastly, you need to create a culture where everyone at your company buys into providing the best customer service out there. As you grow, you want to be able to provide customers with consistent service and ensure team members can step in when needed. It is really difficult to be successful if there are only 1 or 2 people who do it. They key is to get buy in from everyone.