Something I have not seen mentioned yet (from myself included) is battle rhythm.  For sure get that from the RIP, predecessor, or NCOIC. While you get your feet under you, you can at the very least nail the easy stuff and get “brownie points” for taking care of the meetings and facetime that you reasonably should be nailing.

I also saw NTC rotation mentioned. If you’re doing a CTC, get *tight* with your S1 – you guys need to figure out casualty ops together (with the MEDO, preferably…because guess who writes (or should) the Sustainment portions of OPORDS?! good times).  Use that knowledge from being an XO to professionally develop the S1 (explain why something isn’t possible due to company constraints…and then combine your knowledge to figure out a solution), and be open to the opposite.  Frequently, Sustainment problems are solved by a combination of S1, S4, MEDO, and FSC commander combined (which is basically how you prepare for a Sustainment RXL).  You’re going to be an integral part of the success of your unit.  A Company Commander can have the coolest, most effective tactics possible, but it is meaningless without the resources to pull it off.  Go take care of business, man!