Reliability
Clients always track consecutiveness and constancy. They espy how you keep your promises and decide whether it's a nice idea to count upon you or not. Avoid humbling phrases like "hope we manage it" or "we'll try"! The client marks your hesitation involuntarily and then you are dead in his eyes - the words you say turn to jabber. Note that any trifle (down to correct and accurate documents filling and accounts) really matter. You need to be reliable.
Responsiveness & Politeness
Clients want you to understand their inquiries immediately and wait avidly for your actions. They want it here and now, so be prepared. Be attentive to customers' requests and avoid perceiving it as something trifling. Track how sales managers answer calls. Corporate politeness and responsiveness level of all employees getting in touch with clients matters as well.
Competence
Make sure, whether you or your team possess sufficient mastery and knowledge to offer skillfully the products or services you sell and don't. Track updates of the information you provide to customers and ascertain how deep the communication managers (e.g. secretaries, official representatives) understand the subject of your business offer.
Availability
Please, clarify that customers can find your office location easily. Note that the phone line should not be permanently busy and the secretary should not keep the calling person waiting. Business hours should be convenient for customers' visit as well.
Security
Clients want to be assured that they are safe having business with you and using your services. Some companies care about business security neglecting security of clients. That's a flaw: Customers expect you to store their secrets.
Information Sharing
Company representatives should use customer-friendly language leaving technical slang for internal dialogues. Apart from the above mentioned it is very important to be able to reveal persuasively major advantages of your products or services and explain how expenses are formed. Share information with your customers and inform them. Note, that they are extremely curious.
As you see there's no magic. In return, there is a real customer influx.