Get lost and explore!
Dublin was a wonderful city. So many nooks and crannies to find yourself in. Be sure to get to the tourist areas, but also get out and explore more of the areas outside the downtown area. I still like Galway better, but you can't miss Dublin!
Insider Tip:Avoid the heavy tourist areas. Find a nice pub in the outskirts and enjoy the culture and atmosphere of a real irish pub. Explore!