Standard topics are covered are on the MOI, but you always need the NCO and Soldiers Creed, Unit History, Crests, DUI, Unit Awards. I would recommend the 7-22.7 for basic NCO discussions, and knowing your primary weapon.
Practice your creeds and autobiography at the POA. If you can gain access to where the board is held, practice reporting and your movements. Always get with your leadership for their experiences and to set up MOCK Boards.
Hope this helps.