What tips or advice do you have for someone going to their first drill as a newly direct commissioned 1st LT in the Army Reserves?

After the check in process you need to talk to whomever will be your reporting senior to get his/her opinion of your role. Are your immediate responsibilities going to be clinical? Is your unit in a preparatory situation where your responsibilities will be training and logistical or are you augmenting regular forces were you will be filling operational responsibilities? It's like an new job, you need to find out what your boss expects, then work with the other people in your section to move toward the boss's goals, getting guidance from all around you to establish where your section is relative to those goals. Is your particular billet more clinical or are you expected to function as a staff officer? I once worked with a former Medical Officer who confessed that his total responsibility in the service was being a surgeon and his military prowess was limited to knowing how to put his uniform on, which he finally mastered after a couple of months on the job.

As a mustang DCO, I can tell you always listen to your senior enlisted leaders and make sure your enlisted needs are being met. Many prior enlisted don't make the transition easy, so find mentors on the officer side. Always set the example, be a good listener, and know integrity is key. Volunteer for the hard duty. Remember that everything you go is communicating something - what are you communicating? Preparation is critical, so don't show up to any meeting without preparing - and never be late, ever. And, I've seen more than a few DCOs show up with their uniform effed up - have someone look you over beforehand so you don't unnecessarily take arrows on your first day. Good luck!

Have you reached out to your commander? I'd call him or her immediately to get a good feel of what he or she expects from you. Then go in, formally introduce yourself to the commander, First Sergeant, and Platoon Sergeant.

Showing a basic courtesy like this really does go a long way in establishing yourself. When I commissioned, first thing I did was call my company commander for more information on the unit. Then I visited the AGR staff prior to drill for in-processing. They thought I was a newly-enlisted Private! Regardless, it made integrating into my new unit much smoother.