I recommend the Historic Walking Tours of Dublin which depart from Trinity College's Front gate. The fee may be paid to your guide and it's an excellent way to see Dublin's important sites - tours take about two hours.
One of the key visitor attractions in Dublin is St Patrick's Cathedral and many visitors approach it by foot from the nearby Christ Church Cathedral (or many see it by tour bus on the same route).
Ireland's most famous product is Guinness, founded by Arthur Guinness in the eighteenth century. The family were later titled, bestowed with the 'Iveagh' name (Dubliners say "Ivy" but the correct pronunciation is "I've a" with a short 'a'). Remarkably (for such a rich family), they showed great benevolence to their workers, and towards the citizens and fabric of Dublin. The Iveagh Trust administers a large foundation in the name of the family and their legacy continues to this day. They built fine houses and facilities for their workers and provided health and social support to their families. One of the least known Guinness schemes is Iveagh Gardens, a series of houses built in what was the countryside of Dublin, Crumlin. Guinness also built sports grounds nearby, taking the enlightened attitude that happy workers were more productive.
In the city centre, the tenements in the vicinity of St. Patrick's cathedral bear witness to the Guinness's charity (I do not use the term 'tenement' in a derogatory sense - it simply implies a building containing a large number of flats or apartments). They stretch from Patrick's street through Ross Road, Bull Alley street and Bride Street. Included in this grand scheme were the public baths on Bride Street known as Iveagh baths (closed in the 1990s). A notable contribution fo education was the technical school on Bull Alley Street which is still open. Part of the Iveagh buildings include a hostel for the homeless on St. Patrick's street; it is still an important part of Dublin's charitable system.
Arguably, the most important contribution of the Guinness family was the restoration of St. Patrick's Cathedral, at a time when it was literally falling down. Small wonder why you will find a statue of Arthur Guinness outside the cathedral; you will also find the family name if you examine the pews (forms or seating) inside the cathedral.
Jameson whiskey, and its importance within the Irish whiskey industry...coming.