Is there anything I need to know to study Abroad in Ireland for one month while in the National Guard?

Main reason being not so much for safer travel but if you have any run ins with police or civilians abroad it's much better they think you're a dumb tourist instead of picking up the phone and calling the embassy saying "hey we got a soldier of yours"

Wrong answer. You can be accused of spionage if you fail to reveal your military background. They will call the embassy is you get in trouble regardless if you are a tourist. You do not have to share any information, and for safety you can say that you are a student and that's it.

SPC David Willis - I disagree. I would definitely bring my CAC and CAC reader with me, an emergency contact list for CoC, and maybe my official passport packed away just in case, but I would likely avoid hooah shirts and any other "I'm a US Soldier" identifiers. (i.e. duffel bag, UCP/OCP camo items, combat boots, dog tags, gortex, tight reg hair, etc.)

Remember to back up your laptop/phone/camera before you travel and delete things that might get you in trouble or prove embarrassing when inspected by US, UK, or Irish customs enforcement. Log out of all accounts (email, facebook, cloud, twitter, banking, amazon, wifi, etc) and remove all auto-connect/auto-login options (erase usernames and passwords). Enable all password options during travel (power-on, desktop login, screen lock/screensaver, apps, account access, wifi, etc) and disable file-sharing. Consider a burner phone instead of your US smartphone. Encrypt data if possible. (Its often better to put sensitive info on a well hidden small encrypted thumb drive/SD card secured within your checked luggage than saved on your laptop's hard drive or phone's memory -- but I'm just weird like that.)

https://www.eff.org/wp/digital-privacy-us-border-2017
https://motherboard.vice.com/en_us/article/qkvmvq/you-have-no-right-to-electronic-privacy-when-you-cross-the-us-border
https://www.cbp.gov/travel/cbp-search-authority
https://www.cbp.gov/sites/default/files/documents/inspection-electronic-devices-tearsheet.pdf

Contrary to what CBP often claims, you are *not* required to provide them your PIN or password to assist them in searching your electronic devices. However, that tactic might also extend your border delay, especially if they want to get even with you for knowing you are not required to unlock your devices.
https://www.nytimes.com/2017/02/14/business/border-enforcement-airport-phones.html

I should have been more specific in my post. I would also bring my CAC with me, I was more referencing ACU/Multicam backpacks, military themed shirts, desert boots etc...