This is my first year as a mentor for my team, Team Rush 27. I was the driver/operator for our team throughout my four years of high school. Now as a mentor I was given the job of finding and preparing this years drivers for what they are going to experience out on the field. Through my experience, this is what I look for in choosing new drivers as well as the process on how to train them.
First of all, any operator of the robot has to be confident with him/herself. They must not be intimidated easily must know that the rest of their team is going to be looking up to them to make the robot perform while on the field. Even though the team may not be pressuring the drivers to perform to perfection, the drivers themselves will feel that they are, and must be able to handle the pressure. They must also be focused and be able to stay calm as well as still complete the tasks that must be done with distractions. On the field it is loud and can be very distracting at some times, they must learn to stay calm and focus on the job at hand. A major part of being a driver is to be able to communicate well, to be able to communicate to you fellow driver, your coach, human player, as well as the other teams is possibly the most critical component.
When choosing drivers for this season I am planning to go about the following plan:
First, I like to set up an obstacle course. Using past robots, OCCRA or FIRST, I have the students drive through a series of times to get a feel for the controls in their hands. They must “become one with the robot” I guess you could say. Each person has their own individual feel for the robot and they must be given time to find this out for themselves. I would have them driver through a series of obstacle courses each meeting, each getting a little tougher and having them go a little faster. At the end of the obstacle course I make them complete it again, except this time they must drive the robot in reverse. This is a major advantage out on the field, to be able to drive backward, forward, side-to-side and not losing their sense of which joystick to move for it to go in a certain direction As a coach or mentor, you have to provide the students with support, don’t be condescending, think of ways to improve and explain them in a non accusing way. Build trust with your drivers. However the drivers need to understand that you are the coach, and they must respect you judgment while on the field. Oh and another very important thing… If the student makes a mistake on the field, do not tolerate any other students criticizing them after the match. As a coach’s responsibility you must step up and say that you told the drivers what was supposed to be done and they should take any issues to you and not the drivers themselves! Make your students on the team aware that the drivers know if they made a mistake or not, they to not have to be told another 20 times by each student on the team. Our team has a special ritual if you would, that we do after every match. The coaches should be the only people talking to the drivers about their performance and how to improve. We have the team come down to the pits and welcome the drivers and coach no matter what the outcome of the game,the support that they get from the team will only make them better.
After they are getting used to the robot, another exercise is to have the entire team come and watch them practice. This will put an enormous amount of pressure on them in front of the team as well as provide distractions. They must be able to do this, because it will be 10x harder once they have to do it for real in front of hundreds, if not thousands of people at nationals.
If you have a practice field at your disposal, then as soon as you have a moving robot, drive on the field as much as you can practice certain procedures/maneuvers you know you will want to accomplish during a competition over and over again, making it quicker and quicker and until they can do it flawlessly.
Thats all I can think of at the moment, if you have any other questions you can pm me or answer to this post. Other than that, just PRACTICE, PRACTICE, PRACTICE…three key words to success. Good luck!!! 
Crap, I forgot to add one thing. I found this out the the past couple years and I believe that it is a very good idea for any team. If you know who your drivers are going to be…make sure that they are on that sub-team…i.e the chassis driver is on the chassis team and the arm driver is on the arm team. I found that this helps immensely, if the student knows the inner workings of the part of the robot that they are controlling they know a lot about the robot before they even touch the controls!