SGT Promotion board, any advice? What to do/not to do if I don’t know an answer to a question?

If you do not know... There is only one correct answer. "I do not know sir, but I will find out." Then regardless of how the board turns out, find out; and get back to the person who asked you.

don't try to bull shit your way through a question. The board will see right through it and can actually be more of a negative thing then just admitting that you don't know. If you don't know the answer to a question, admit that you do not know. Then elaborate on the steps you can take to find the answer.

Know the NCO Creed. Know your 10 level tasks and some of your 20 level tasks.