Will,

Here’s my advice in no particular order.  This isn’t an exhaustive list, but it is a start.

As Ray said, pick a reading list and read.  Your school house will have one, but don’t constrain yourself just to that.  Always prep for the next job.

Systems–

Command Supply Discipline Program
TAMIS – Total Ammunition Management Information System
DTS – Defense Travel Service
DTMS – Digital Training Management System
CATS
PBUSE – Property Book Unit Supply Enhanced
MEDPROs – Medical Readiness
TRiPS – Travel Risk Planning System
GRAT – Ground Risk Assessment Tool
Risk Management and Safety Website

Forms/Regulations —

AR 25-50, Preparing and Managing Correspondence – seriously, read this.  Build Word templates for yourself.
AR 220-45, Duty Rosters
AR 350-1, Army Training and Leader Development
AR 385-10, The Army Safety Program and Risk Management Worksheets
OER and OER Support Form, as well as AR 623-3 and DA Pam 623-3.
Similar to the above, be familiar with the NCOER and its support form.
DA31s for leave/pass
DA 4856 for counseling
Family Care Plan and its Checklist
Key Control Register