Help put customers in the best banking products for their needs, and service any existing accounts.
A great day would be helping a new customer set up their new account(s), and show them how to use every benefit of the product they are getting. Walk them through any questions they have including using their debit card, showing them how to bank online, and getting them comfortable using their new bank.
You need to have the ability to talk to customers on two levels. On the first level you need to make it personal, have small talk, get to know the customer on a personal level. Then you have to guide them in a professional manner to help them choose the product that is right for them. To the customer we are the expert and they want to use our knowledge, but to make them feel comfortable you need to be able to relate as another human.
Here's the first step for high school students
Get comfortable speaking to strangers. Be able to feel their vibe and adjust your own vibe to meet with theirs. This will allow you to relate best with someone you don't know.
"You NEED to go to college. - My mother."