First of all, Galway is a beautiful city. It's in the west of Ireland and is full of traditional Irish culture, much more than Dublin, which is a lot more cliche for the benefit of tourists. You truly get the sense that you are in Ireland when you are in Galway. Be sure to take in all the street performers and the Marketplace that happens each weekend.
More insider tips of where to go: King's Head pub. It's great, and claims to be the oldest pub in Ireland. In the beginning of the Spring Semester they host comedy nights. Be sure to check them out! Griffin's Bakery is delicious. You're going to want to eat there all the time. Finally, don't be afraid of the clubs in Galway. Clubbing is a part of the culture, and chances are you will eventually go. Just be smart and stay safe and you will be fine.
The program director, Dermott (Call him Derm) is absolutely amazing. He is a great guy and a great program director! The group that I was with was his very first group and he handled everything so well right from the beginning. He is easy to talk to if you need help, and his office is almost always open, so make sure you visit him! He's absolutely awesome!
NUIG is a great university. The only thing you need to be prepared for is a lot of independent studying. That is the major focus of Irish education. Independent studying, with one final exam at the end. You still have to go to class, though, so don't think you can get out of that.
The excursions are fantastic! You'll love them.
Finally, the weather. Don't bother bring an umbrella, it'll just break. Don't bother bring rain boots, they are a sure way to tell you're American. Bring a jacket that can withstand water and is warm. It'll be your best friend.
Most of all, enjoy your experience in such a beautiful and awesome city, and don't be too sad when you have to go, because you know you will be back one day!