It is better to know things before going to another country as you can cause the awkward situation or might be one will be on the hot seat when you have done something. That is why if you will also go to Ireland do not say that all people their have red hair. One important thing to do is that do not tell Irish people that they drink all the time. This is a tip given by an Irish and he added that you must not make fun of the sports in Ireland.
Also, it is important to understand what they say as it is not all are literal. Greeting also is one that you must learn. It is rude not to greet someone back. Most people give this an importance. So prepare your smile and have fun. Another thing is that you must take note that in the road you will drive on the left part and not the usual right part. You do not want to cause an accident as just the others. When you are under the age of 18, you are forbidden to drink in the public places.
In terms of smoking, look for places not enclosed and are considered public and also not in the workplaces. When you are in with someone having a drink in a pub or bar, you should take turns in having your drink. When you finish, wait for all to be done before you drink again. Also, do not always compare something from Ireland to the other places like sunshine or food or anything else.