"I am never afraid of what I know."
Anna Sewell (1820 - 1878)
Get to know more and more about more and more things, you will be less and less afraid of less and less things. Biggest fear is fear of uncertainty. Fear of unknown. Fear generated by speculation.
First thing to do is to eliminate as much uncertainty as possible. We imagine lot more uncertainty than that is really there. We do not ask questions when we can. Instead we speculate and there is no end to imaginations especially when it comes to worst case scenarios. Mind is hyperactive in churning out all doomsday scenarios.
Fear of unknown is much easier to handle. Today, with information about everything available mostly for free on the Internet, there is no excuse not to be able to research and learn what we do not know but need to know. For example, a friend learnt most of the chores of home maintenance such as repairing appliances, understanding jargon of plumbers etc. by going thru material on the net, books etc. It was not his intention to perform those repairs by himself. He wanted to understand and be in control while dealing with professionals doing those jobs. Being able to ask right questions goes a long way to help reduce the stress from unknown. Ask one right question and the person answering invariably educates you more than you had hoped for.
One more important point regarding dealing with uncertainty is to reduce the probability of uncertainty. Typical risk management. Four ways to deal with a risk - accept and move on, mitigate, transfer and avoid. All these are valuable depending on the risk and what is at stake. It is not true that you have to deal with the risk all the time yourself. Why do we buy insurance? Insurance is the best example of 'transferring' risk.
Some of the examples here can help understand general strategy to reduce uncertainty. Many smart people go to the place of their interview well in advance and figure out everything so that they can reach right in time and free of stress so that they can do their best in the interview. They drive to the place under similar conditions that will be on the day of interview, deal with traffic, deal with parking, deal with security and so on. Basically a mock run. They add contingencies for traffic jams, programming required contact numbers on the speed dial so that if you are stuck in the traffic you can call easily without having to take away too much attention from driving. This is a very smart thing to do. Once you have done the mock run, you would feel so relieved that you feel it and your prep goes very well.
Another example a friend had quoted is also very educational. His wife was appearing for the bar exam which was being held in some downtown area. In order to reduce the time required to commute and the risk, they took a room in a hotel right opposite to the place where bar exam was being held and stayed there for 3-4 days. They had a great stress free time. She could study at peace and relax as needed and do best in the exams. This was a very smart thing to do when stakes are really high. You miss bar exam and probably you have to wait good number of months before the next chance. Think of the opportunity cost of being without licence for a budding lawyer.
If you are traveling to other cities for interview, always ask to be flown in at least a day in advance. As such you have a lot to figure out and last thing you want is to land on the day of interview after a long exhausting flight, getting lost in a new city and managing to show up good 2-3 hours after the interview. This is not all uncommon. Ask people who went to cities such as LA, NY, Boston etc. and sometimes they got lost so bad that there was no point in showing up at all because it was time to return when they had found the place. Also, investing in a good GPS is a very smart thing. Program your route in advance and let GPS take care of directions. Since technology is always prone to failure, paper maps are still required for back up.
There are so many things we can do proactively many times with only little extra money which go a long way in reducing uncertainty and unknown. Accordingly our fear goes down and our mind does not dwell on things that are of no good use.