An important skill for anyone who provides service over the phone is communication, which includes these 3 elements: credibility, connection, and logic.
Credibility means you know your stuff and demonstrate that knowledge.
Tip: Be conscious of any long silences on your calls. You may very well be looking at their account and working on solutions to their problem, but they don’t know that. Let them know you're still there by saying something like: “let me look into this for you” or “one moment while I review your account.”
Connection means your caller needs to know that you care, that you value their business and that you want to help.
Tip: Repeat their concern back to them with empathy. Try: “I understand how urgent this is..."
Logic means your solution has to make sense. To them.
Tip: Avoid both company and industry jargon. Speak in plain terms and explain next steps as clearly as possible.
If the answer to: "Can I help you any further today?" is "No, thank you, I understand perfectly." then give yourself a pat on the back. Job well done!