When the general public thinks of any job associated with a computer, people skills do not come to mind.
Reclusive. Out of touch. Nerdy. You know — a real weirdo.
These traits worked fine until everyone got a computer. Now a computer specialist not only needs to be the smartest man or woman in the room, they need to be the sanest, most communicative and most sympathetic.
Which brings us back to smart. Just to take you down a peg, you are NOT the smartest; the people who need your support are. They know how to run their business; you don't. Listen. Learn what their problems are. Respect their experience. Don't BS. Don't talk down to them.
Speak their language, whatever it happens to be; not gobbledygook.
Throwing tech-speak around doesn't make you sound competent, it makes you sound incomprehensible. Explaining the problem in "humanese" makes you part of the team as opposed to an out-of-touch, alien life form.
Don't lose your cool even if everyone around you has lost theirs.
Situations arise in the support world where you want to tell your client or coworker, "This is a disaster. No hope in sight. Shut down the system and go home." Rarely is that is close to the truth, but it can sure feel that way. Every problem is fixable. The looming question is "how long will it take to fix it?"
The most honest initial answer to the how-long question is, "I don't know." It may not be the answer everyone wants to hear, but it gives you a bit of breathing room until you know more and can give an informed response.
Swallow your pride and ask for help if you need it.
There is a certain "I can handle it" swagger that comes with the job. You wouldn't be doing support if you weren't good at it; but if you're stuck, don't waste the company's money by trying to tough it out on your own. Yes, you can probably work through any problem given enough time, but time is not on your side. The longer it takes, the more incompetent you look and the higher the stress level becomes.
Don't forget to stay in touch.
After everything has settled down and the workplace has gone back to something approximating normal, check in to find out how it's going even though you already know it's fine. Supporting computers means supporting people. That's really the most important part of the job.