There are some specific unique things about Ireland. Firstly, it uses the Euro Currency system.
The public transport system is very good so you do not need to hire a car. The public transport system can take you all parts of Ireland.
There are a lot tour operators in Ireland so this is an efficient way to tour the country. There are also a lot of tour groups who travel to the Aran Islands.
The weather in Ireland is very mild so it is a good idea to have at least one of layer of clothes for a good day and 2-3 layers for a bad day. Remember that the weather in Ireland is very changable. It rains regularly in Ireland which is why the landscape is so lush so it is a good idea to have water resistant clothing handy. An umbrella is also useful.