I’ve been to Ireland 5 times (so far). I have the good fortune to have some great Irish friends so going to Dublin is not a typical tourist experience. I’m picked up at the airport and driven around town like visiting royalty. The trip is mostly planned out with pub nights (almost every night), dinners and visits to worthwhile venues. It’s great fun and gives a very local perspective.
As a local, you DON’T go to Temple Bar (“it’s too damn expensive”); you don’t go to the Guinness Storehouse Tour (“I already worship Guinness- every night”); you don’t limit your shopping to Grafton Street (“stay north of the Liffey with fewer tourists”).
As a local, you DO go to your “local” (the pub in your neighborhood where you know almost everyone who walks in the door); you do have your regular shops (like the Bretzel Bakery where they know you and your order as you walk in); you do order multiple drinks at last call (because the barman can’t leave or kick you out before you are done).
As a tourist, you should go and see the Book of Kells, Christchurch Cathedral (the basement is spooky), and the Kilmainham Gaol Tour (Old Dublin Jail from the 1800s). Entrance to all museums, including the National Gallery, the National Museum of Ireland and Trinity’s Douglas Hyde Gallery, is free. You might notice a lot of taxis – there are in fact more taxis in Dublin than in New York City! Dublin is a great town with lots to see and with lots of great people.
Whatever you do, don’t call an Irishman “British” (the Republic of Ireland is not part of the U.K.). And don’t stop for the weather, i.e. rain. It’s either about to rain or will rain later in the day. Bring rain gear and enjoy. It’s all part of Ireland.