For example, do you offer a ticket system or some way to track issues that arrive? You can provide all the support you want, but without tracking ticket numbers, both you and the customers are going to be lost. It's also wise to have a built-in auto responder on your ticket system so that customers are greeted immediately after submitting a ticket.
While support and IT customer support issues can give back in a million directions sometimes, you want to be able to give customers a window of your time in which they can expect their issue to become handled. Whether they are calling you to definitely work on a network of computers within their business, or you're coping with different type of job, you should give them a time frame.
When you are out there on a job with a business, you're dealing with people inside their office and helping them with something they don't know about. This may make things get quite casual pretty quick because both sides let their guards down. However, case a friendly reminder that just as one IT support professional, you have to be 'professional' at all times.
Every business needs great customer comments. That being said, after you've solved a large technical issue for an organization, this is a great time to try to get feedback at their store. They will be likely to give you a glowing review, which you can use to help get more business. You may also offer a referral program.
Something else you can do is to use check in system to take the opportunity to make personal responses as often as possible. Address customers by name, and you will even call them regarding tickets if need be.