If you've got the main Dublin sights ticked off, my honest advice is to give yourself a couple of days outside the capital, because that's where Ireland really opens up.A few I'd point people to:
1) Drive a stretch of the Wild Atlantic Way. You don't need to do the whole thing. Even a day or two around west Clare or Connemara, with the cliffs, the small harbours and a slow pub dinner, gives you the version of Ireland most people are actually coming for.
2) Pick one smaller coastal town and stay the night rather than day-tripping out and back. Spots like Westport, Kinsale or Dingle have great food and live music and are far easier going than the big tourist stops.
3) Don't over-plan. Some of the best afternoons here come from pulling into a random village, finding a café or a trad session, and letting the day drift.
Happy to help if anyone's trying to piece a route together. What sort of trip are you planning, more coast and scenery or cities and culture?